Hardwood Floor Problems: Heed the Warning Signs

The moisture content (MC) of wood, must be managed to achieve optimum beauty and durability. When relative humidity (RH) rises, wood absorbs moisture from the air. When RH falls, wood loses moisture to the air. This is a completely natural process, but excessive MC changes can cause wood floor water damage.

Wood Floor Problems Caused by Excessive Moisture

Most problems with wood floors are caused by too much moisture. These are some of the most common causes:

  • Water on or under the floor
  • High humidity
  • Improper or no acclimation
  • Poor installation

Water on or Under the Floor

Any moisture that comes from below a subfloor or gets between the subfloor and the flooring can cause problems over time. Leaking appliances, groundwater intrusion through a perforated vapor retarder, condensation, and even moisture from a concrete subfloor that had not completely dried can introduce moisture to your flooring.

It might be the terrain of the site with rain and runoff not moving away from the foundation that can cause moisture-related problems with the wood flooring over time. Recent flooding or even spills that aren’t quickly and completely cleaned up could also be a problem.

High Humidity

If you live in an area with humid weather, the floor can absorb moisture from the air during humid months. This will cause the wood to expand and can cause problems.

Improper or No Acclimation

Before a wood floor is installed, the wood must be “acclimated” to the average temperature and humidity of the space where it will be installed. This means it must be stored in an area with similar conditions and allowed to either absorb or lose moisture to the surrounding air until it stabilizes.

Once it stabilizes, it won’t expand or contract as long as the surrounding conditions remain constant. If the floor isn’t properly acclimated before it’s installed, it will expand or contract after installation and cause problems.

Poor Installation

There are several ways a poor installation can cause flooring problems. Some mistakes will not allow the floor to move as it absorbs moisture. For example, the planks might have been installed with the wrong size fasteners or not enough fasteners.

For instance, there might not be adequate expansion gaps around the perimeter of the floor. For large expanses of floor, there might not be adequate expansion joints. This can cause buckling in the floor.

Other installation mistakes can allow the floor to absorb too much moisture. The subfloor might have been too wet when the floor was installed over it. If the subfloor is concrete, it might not have a vapor retarder installed underneath. If it’s wood over a crawl space, there might not be vapor retarders installed in the crawl space or on top of the subfloor.

Common Hardwood Floor Problems and Visible Signs

Some moisture-related problems are visible to the discerning eye. Primarily, wood flooring problems can occur when the wood expands and contracts. This “wood movement” occurs naturally according to seasonal shifts or when ambient RH levels change in the home. These changes can also present a less-than-desirable change in the appearance of your wood flooring.

Wood Floor Problem

Cracks and Separations between Boards

When homes are heated in the winter, RH levels can plummet, boards can shrink, and spaces appear between the boards as the wood loses MC. Some of these variations are seasonal problems and will close up on their own when the weather (and related RH) changes and the MC of the air increases.

Monitoring the room’s temperature and RH level, then taking corrective action, can also minimize seasonal shifts in the wood floor. As an example, homeowners can add moisture to the air during dry winter months by installing a humidifier in the furnace.

hardwood floor cupping related problems


Cupping is when the edges of a board are higher than its center due to moisture, which causes the wood to expand. Cupped floors can occur after water spills onto the floor and is absorbed by the wood.

However, usually high RH is the culprit. As the wood expands, compression can result as the boards are crushed together, deforming the boards at the edges.

Hardwood floor cupping is caused by a moisture imbalance through the thickness of the wood. The wood is wetter on the bottom of the board than on the top surface, which dries quicker than the bottom.

Cupping most often appears after the floor has been installed and in some cases, the floor will cup even if it was installed correctly.

Learn if cupping can be fixed or not in our article Can wood floor cupping be fixed?


The opposite of cupping, crowning occurs when a board’s center is higher than its edges. A common cause is moisture exposure or imbalance. If the surface of the floor is left exposed to water or left in humid conditions for an extended period of time, the moisture can saturate the wood flooring and cause crowning.

Another cause is that the floor was previously cupping, but was sanded before the MC returned back to its normal state. In this case, the floor should be given time to dry before sanding. The sanding process can cause the raised edges of the board to flatten while lifting up the middle of the board if the floor is sanded while the boards remain cupped and moisture is still present.

hardwood floor buckling problems


Floor buckling occurs when the wood flooring pulls up from the subfloor, lifting several inches in one or more places. Buckling floors is the most extreme reaction to moisture in a hardwood floor.

Fortunately, this is not a common occurrence. Floor buckling happens most often after a floor has been flooded for an extended period of time.

If caught early, spot repair and replacement may be possible. Once the standing water is removed, several boards can be taken up from the floor so that the air can circulate across and below the floor. Hardwood floor repairs can usually be made when the floor has dried to a more stable moisture level.

Wondering why your carpet smells? It could be from moisture issues in your hardwood flooring causing your carpet to smell.

How to Prevent Hardwood Floor Buckling and Cupping 5 Tips

1. Acclimate the Flooring

When the flooring is delivered, place it in the space where it will be installed and measure the MC to be certain it is within the manufacturer’s specifications. If it isn’t, allow it to acclimate for the specified time and measure again until it is within spec.

2. Cover the Subfloor with a Moisture Retarder

If this is a nail-down over a wood subfloor installation, lay down a moisture retarder over the subfloor before installing the wood flooring.

3. Provide an Extra Moisture Retarder

If the installation is over a crawl space, make sure there’s a moisture retarder in the crawl space and install an extra one if the existing one is in poor condition.

4. Use the Recommended Fasteners

Use the recommended number and type of fasteners when installing the planks to a wood subfloor. Inadequate fasteners will allow the floor to move too much. However, don’t over-fasten or use too large fasteners, or you might crack the planks.

5. Check the Moisture Condition of Subfloors

Determining the MC in a wood subfloor is essential to quality control when installing hardwood flooring. Flooring installers must know the MC of the subfloor as well as of the wood flooring. Test for moisture at several locations in the room – a minimum of 20 per 1,000 square feet – and average the results.

You should make sure to measure all exterior and plumbing walls. In most regions, a dry subfloor that is ready to work has an MC of 12% or less. If you record high MC readings, do not proceed with the installation until the origin of the moisture is identified and all moisture-related problems are remedied.

A wood moisture meter is essential for this job. Pinless moisture meters for wood can measure the MC below the wood surface without doing any damage to the wood flooring. Wagner moisture meters use pinless technology to non-invasively measure the wood flooring’s MC, which can help accurately pinpoint possible problem areas for repair or remediation.

The line of Wagner moisture meters, Orion®, can measure hardwoods, softwoods, and exotic wood species. When MC management makes all the difference, using an Orion wood moisture meter is an invaluable way to effectively resolve the warning signs on wood floors.

All types of flooring are susceptible to failure if moisture conditions are not properly monitored and maintained. When the subfloor is concrete, a moisture problem may begin long before the flooring is installed. If the slab has not been properly dried, moisture problems are almost guaranteed with wood flooring applications. Accurate moisture testing is critical for any concrete slab.

The RH test using in situ probes is the scientifically proven most accurate for moisture in a concrete slab. This test is the basis for the ASTM F2170 standard. The Rapid RH® L6 system is the fastest, easiest way to test concrete moisture in compliance with ASTM F2170.

How to Care for Hardwood Floors to Avoid Cupping and Buckling

The most important thing to remember about caring for your wood floor is to keep moisture away from it. Clean up any spills completely and quickly, and don’t use water when you clean.

Dust and sweep your floors daily. Vacuum and mop with a spray hardwood floor cleaner weekly. Set your vacuum on the hard floors setting so the wheels and beater bar don’t touch the floor.

Ways to Fix Minor Moisture-Related Problems

Wood floor buckling can sometimes be solved simply by adding weight to the floor until the extra moisture dries out and the planks level out.

If the problem is more serious, then it’s probably because of an excessive amount of moisture from flooding or a plumbing leak. In that case, you’ll first need to fix the problem, then pull up some planks to allow air to circulate and dry out the moisture.

Once the floor is dry, assess the wood floor water damage to see if you need to replace any planks.

If moisture isn’t the problem, it could be an installation problem that will involve a call to the installer.

Three Invisible Moisture Problems

Some moisture dynamics can occur beneath a flooring substrate, potentially devastating consequences for wood flooring applications.

1. Wood Subfloors

Determining MC is essential to quality control within the flooring installation process. Flooring installers must know the MC of the subfloor as well as of the wood flooring. Test for moisture at several locations in the room- a minimum of 20 per 1,000 square feet- and average the results.

You should make sure to measure all exterior and plumbing walls. In most regions, a dry subfloor ready to work has an MC of 12% or less. If you record high MC readings, do not proceed with the installation until the origin of the moisture is identified and all moisture-related problems are remedied.

2. Concrete Subfloors

All types of flooring are susceptible to failure if moisture conditions are not properly monitored and maintained. When the subfloor is concrete, a moisture problem may begin long before the flooring is installed. If the slab has not been properly dried, moisture problems are almost guaranteed with wood flooring applications.

Accurate moisture testing is critical for any concrete slab. ASTM International has provided several standards for testing moisture with two different test methods before installing flooring over a concrete slab: in situ probes per ASTM F2170 and calcium chloride testing per ASTM F1869. The best indicator is RH testing using in situ probes per ASTM F2170.

3. Leaks or Water Intrusion

Any moisture that comes from below a subfloor or gets between the subfloor and the flooring can cause problems over time. Leaking appliances, groundwater intrusion through a perforated vapor retarder, condensation, and even moisture from a concrete subfloor that had not completely dried can introduce moisture to your flooring equation.

Also from the outdoors, the terrain of the home’s lot with rain and runoff not moving away from the foundation can cause moisture-related problems with the wood flooring over time.

The Antidote

The best cure is to accurately measure and assess the moisture in the subfloors previous to wood flooring installation and also measure the MC of the wood flooring before, during, and after the flooring installation.

A wood moisture meter helps wood flooring lovers to navigate naturally-occurring seasonal MC changes on a regular basis. Pinless moisture meters for wood can measure the MC below the wood surface without doing any damage to the wood flooring.

Wagner Meters uses pin-less technology to non-invasively measure the wood flooring’s MC, which can help accurately pinpoint possible problem areas for repair or remediation.

Wagner Meters manufacture moisture meters for wood that can measure hardwoods, softwoods, and exotic wood species, and also manufactures specialty meters for wood finish applications. Wagner Meters also manufactures RH in situ probes for testing concrete slab subfloors.

When MC management makes all the difference, using a Wagner Meters wood moisture meter is an invaluable way to effectively resolve the warning signs on wood floors.

A Couple of Common Questions

What causes wood floors to buckle?

Floor buckling is the most extreme reaction to moisture in a hardwood floor. Buckling occurs when the wood flooring actually pulls up from the subfloor, lifting several inches in one or more places. Fortunately, this is not a common occurrence. Floor buckling happens most often after a floor has been flooded for an extended period of time.

What causes wood floors to cup?

This is when the edges of a board are higher than its center, due to moisture which causes the wood to expand. This can occur after water spills onto the floor and is absorbed by the wood. However, usually high RH is the culprit.

As the wood expands, compression can result as the boards are crushed together, deforming the boards at the edges. Cupping is caused by a moisture imbalance through the thickness of the wood. The wood is wetter on the bottom of the board than on the top surface, which dries quicker than the bottom.

Learn the pros and cons to water popping hardwood floors.

Elevate your woodworking and construction projects with our Free Wood Moisture Testing Webinar. Gain invaluable insights from industry expert Jason Spangler in just one hour. Reserve your spot now!

Last updated on May 28th, 2024


  1. Emanuelcunningham says:

    After your blog, I know those moisture signs

  2. Thank you for sharing this knowledge. Knowing this will help us to find the cause of the problems and give us an idea of how to prevent them. Nice post!

  3. Gee says:

    I have 24 year old wood floors in a dining room which are starting to cup in a certain area. The flooring is laid over ductwork which is in the ceiling of the basement below. It is not noticeable unless i drag my foot across and I can feel the difference. What could be the likely cause and how to remediate before it becomes more prevalent? Thank you.

  4. Julie says:

    Hi there –

    I have noticed a few areas of my flooring, what are seemingly right above the ducts of the unit below me (condo building) start to gently crown. She is adamant that there is not excess moisture in her unit / she is noticing no wetness. Would you be able to give some insight as to why these areas are starting to gently rise? It is very gentle at this point – only I would notice probably as I feel it daily – but would love to catch anything before it gets potentially worse.

    Thank you!

    • Jason Spangler says:


      Thanks for the question. I need to make sure we are talking the same “language” before I try to answer your question. Is the center of the floorboard higher than the edges or are the edges higher than the center? I look forward to your response.


  5. KJ says:

    Hi, i have a hardwood floors which it become like have a stains . Installation made in may & not yet varnishing it . Planed to install the furniture cabinet first . To avoid my floors from any damage, i do ask my building team to cover up the floors with a canvas . But after that my wood floors become soo ugly (have the stains ) .

    I have call up the installer (Wood Installer) to look up if got any moisture come from the underlay (cement) . The moisture is normal, the unnormal is only for the wood which had the stains .

    My question is.. are the Blue Stains causes from the recover canvas ?

  6. Moises Zubiaur says:

    Hello, I installed a brand new Amana dishwasher and I made sure there’s no vibration or water leaks or steam coming out it and the technician did the same. However, every time I use the dishwasher the baseboards behind the dishwasher separate from the wall and the wood floor behind it looks a little wrinkled. Nothing like this happened with the old dishwasher and there’s no cupping signs either.
    Has anyone had something like this?

    • Jason Spangler says:


      Thanks for the question. I have not had this specific situation come up if there wasn’t some type of leak and/or increase in humidity due to the temperature from the dishwasher. Good luck.

  7. I am happy to reread this. It refreshes my knowledge of woodworking. Nice post!

  8. Jdie says:

    I had a hardwood floor installed 6 months ago over an old wood subfloor. My property is heritage and has a lot of dampness. The new floor is like a rollercoaster to walk on (the floor people claim that it must have been like that before – it wasn’t!) and after heavy rain I have noticed actual small 10cmx10cm pools of water in 3 spots in the middle of the floor of two rooms. There are no drips anywhere on the walls or the ceiling. Do you have any idea how this could be happening?
    There has been a huge amount of movement in the floor – no moisture barrier was used and the wood was not acclimated at all – delivered minutes before they started laying it (and it was all done in a day). Some of the wood was even left out in the rain for a day before they installed it. There is cupping to a minor degree throughout the floor now.

    • Jason Spangler says:


      Thanks for the questions. There could be all kinds of little things or a few big things causing these issues. The one thing for sure, though, is it sounds like there is a moisture problem. Your best bet, to begin with, would be to have a flooring inspector come out and evaluate the project and try to determine the cause so you can start working on a solution. It might be good to start here Certified Wood Flooring Inspector Search | NWFA (woodfloors.org)

      Good luck.

  9. Vintage & Specialty Wood says:

    My family used to love wood flooring, and I don’t blame them because I like the beauty it gives in our home. I like the character and benefits it provides in our home. Anyway, thanks for posting about wood flooring and giving us insights about signs of problems. I am a big fan of woods. Great post!

  10. Enrico I Mignone says:

    Hi, i am having a similar problem. I have a 10′ wide plank walnut floor. We bought it as it already had imperfections with holes in it and knots. We installed the floor in 2014, but just in the last 2 years, the boars are getting some dark lines in the grain, and they end up splitting in those areas. Also getting alot of cracks. Were the previous holes were, they are getting bigger, and now holes are developing. The holes are starting at all the knot areas, and even on the clean parts of the floor are developing black dots and they grow and become small holes. I had a termite guy come and say it wasn’t termites. I had a wood installer come and say thats natural for the wood to move like that, but he thought the cracks would close in changing seasons, and they havn’t. The floors were glued and nailed at the time of installation.

    • Jason Spangler says:


      Thanks for the question. I would recommend that you contact The National Wood Flooring Association at Certified Wood Flooring Inspector Search | NWFA (woodfloors.org) and find an inspector in your area to look at it and give you a formal opinion. Good luck.

  11. Reeta says:

    Thanks for mentioning that most solid wood floors are pre-finished. I’m thinking about getting some new floors in my living room sometime this year. It would be really great to get some oak floors or something akin to that.

  12. Michelle Catapang says:

    Excellent content! Thank you for sharing pieces of knowledge.

  13. Marcus Wong says:

    Your post was very nice and very informative. Thank you for telling us about the hardwood floor.

  14. AJ says:

    We have an apartment with parquet floors in NYC ( concrete below). We bought 3/4 solid rift sawn white oak to install on top. But now seeing comments to not do that. Will we have issues? Need to make a decision to remove flooring asap.

  15. Fran Kaufman says:

    My home was built in the late 60’s with oak hardwood floors. It was carpeted until about 10 years ago when i had the floors sanded and stained. We rarely wear shoes in the house so they still looks great. The problem is at the top of the stairs ( Hi Ranch ) – so center of the house outside the kitchen with the highest traffic – the boards seem to have a lot of give now. It looks fine, but under your feet, you can feel the movement.

    • Jason Spangler says:


      Thanks for the question. I wish I could give a definitive answer. My best guess would be that possibly the fasteners that have worked have loosened due to traffic, so the boards aren’t as tight to the subfloor as they once were.

  16. Dave S says:


    I live in a multi-unit condominium and the unit above mine has HW floors which were installed about two years ago. The noise from from these is horrendous. At best they creak loudly when the person above is walking and there are also “banging” noises which raise the noise level in my unit by 8-15 decibels when measured with sound-meter.

    The building is wood-framed constructed in 1966 and there is no insulation between units. Also, it is suspected no sound barrier was included when the floor was installed.

    Based on the above, I’m curious your opinion of causes/potential solutions to the problem. The unit owner and the HOA are completely uncooperative thus I’m wondering what I can do to: 1) Definitively prove there is problem/deficient condition and 2) Whether there are measures I can take from below to alleviate the noise without spending an inordinate amount of money?

    • Jason Spangler says:


      Thanks for the email. I would research and see if your area has some type of noise requirement for multi-family residential units of this nature. If there are, then documenting the noise levels in your unit and providing the information to the HOA should help. The only other suggestion I may have is to consult an insulation contractor and see if they can give you suggestions.

      Good luck.

  17. Lisa Thomas says:

    Hi — I have a hardwood floor that was laid on a concrete slab. It’s a floating floor. It is buckling and have discovered that the slab has high moisture. Do you have any ideas on how to solve this? Do we have to pull it up or can we mitigate somehow outside of the home?

    • Jason Spangler says:


      Thanks for the question. Based on the information, you state the “slab has high moisture.” You need to rule out any leaks or drainage issues. Once you have ruled those out, you will need to determine how bad the moisture problem is (measure it) and then look for a suitable solution that may involve a sheet or liquid applied vapor retarder. Good luck.

  18. Stephen Marck says:

    Hi there

    Thanks for your reply. Much appreciated.

    I omitted to mention that there are Airbricks in the damp course (base) of the property, that had been covered up in previous years. when renovating we installed new Airbricks in their place. As this room has a large bay window, it is also the coldest room on the property. To help with that we installed Window Shutters, which help with drafts from the double-glazed windows but which causes a cold air trap, and thus condensation between shutter and window on colder days. As previously mentioned the dampness/smell only occurs nearest the outer walls not partition walls, We tend not to open windows in this room in winter months as we then get damp patches appearing on the ceiling coving above the open windows.

    I was wondering if the previous owners had sealed the old airbricks due to similar problems?

    No sign of cupping or distress, but will keep checking.

    Any other suggestions you might be able to offer?

    Thank you

  19. Chelsea says:

    Hey Jason,

    We live in Texas in a peer and beam home that was built in 1965. We purchased the home 3 years ago and after our snowmageddon happened and the weather warmed up we notice the floors beginning to shift and raise or buckle. I do believe the floors in the home are the original. I started researching that it was probably because of the humidity under the home but then the weather just cooled off and the floors went back down. Now that they have gone down we are now noticing the opposite problem which is our floors have dipped down and cracking has begun. We have never had a flood in the house or anything like that since living here and I’ve done a lot of research on wood floors in peer and beam homes. I’m curious what you suggest to help fix both of these issues once it warms back up? Is there anyone you reccomened that is a contractor that works in the DFW area of Texas that I can call to come look at our floors to see about the damage? In addition we do have some small hole spots in areas around the house that I need fixed anyways that have developed since we moved in. I need someone that knows what they are doing with peer and beams homes and can help us fix the issues we are having or come up with a solution of possibly putting a new floor in that won’t cause this many issues.

    Thank you,

    • Jason Spangler says:


      Thanks for the comment. Your best bet would be to go to http://www.woodfloors.org and in the top right corner it says “hire a professional”. These are people that have had various trainings and certifications by the National Wood Flooring Association. There should be someone on this list that can help.

      Good luck.

  20. Stephen Marck says:

    Hi there,

    I laid an engineered oak floor on top of a fibre/aluminium membrane, a few years ago in my lounge, in my UK home (built circa 1900’s). The house has brick foundations with a wooden subfloor built over wooden battons and has airbricks that allow air to go through the void., leaving a 2-3 foot gap between ground and sub floor. The House itself is built on a hill, clay soil where an old spring runs downhill at the back of the properties in my street. Being an old house, built of bricks and mortar, it is suseptable to damp on the outwer walls (semi detached). However, in the loung where I laid the floor just 3 years ago, we are now getting damp floor in places and where the underside of furniture get’s mildew. We do use a humidifier thoughout our home from time to time if needs be.

    I checked underneath the subfloor, no sign of leaks from central heating pipes or visible sign of water at ground level. In fact the underneath of the subfloor seems dry.

    My question is, could the issue be moisture on the brick foundations that is going into the flooring causing the damp or something completely different?

    • Jason Spangler says:


      Thanks for the questions. I would think if the moisture causing the mildew was from below that the engineered oak would also be showing signs of cupping or other distress. I would recommend monitoring the interior relative humidity and temperature over time to see if fluctuations in the interior air may be causing it. Additionally, I would also check the ventilation in that 2-3 space under the subfloor to ensure you have enough air movement alleviating the potential for moist, stagnant air.

  21. Rachel Humphrey says:

    Our house was built in the early 60’s oak floors through out. We took all the carpets out and the floor seems a bit cold but not sure if they are insulated or not. They don’t seem cold enough to not be. But was wondering if there is an easy way to know. We do have a crawl space but unless I have to would rather me not go under. Lol what are the odds they are? The floors are great minimal sqeeking and none broken or dinged up. Just need cleaning and refinishing.

    • Jason Spangler says:


      Thanks for the question. I would doubt they are insulated. Many times homes will have “trap doors” inside, usually in a closet. These give access to the crawl space and to possibly be able to see if there is indeed insulation. Good luck.

  22. Vanessa Phearson says:

    I have a very unique problem. I was hoping to speak with you to explain and see if you can help me?

  23. William says:


    Thanks for a great and helpful article.

    We had a refrigerator leak that sent water under the edge of a floating floor. The water leaked from a tile and went under a doorsill. We removed the sill. There is a gap between the tile and the edge of the the flooring that is about one half of an inch wide. The moisture barrier appears to be totally saturated, because when we jump on the floor, water squirts out from underneath it. I am running a fan that blows air across the floor surface and keeping humidity as low as possible.

    I can think of two other measures that might help dry out the wood and wanted to know if they are safe. One thought I had was to use a space heater to warm up the top of the floor. Another idea I had was to put shims under the edge of the floor and blow air under the floor. Would either of these measures be safe, or would they increase the risk of damage to the floor?

    Thanks for your help,

    • Jason Spangler says:


      Thanks for the question. Not sure I have experience with either potential solution, but if I were to use one I believe it would be your shim suggestion. Good luck.

  24. Heather Ritchie says:

    I want more than anything a 10″ wide custom solid hardwood floor, but am discouraged about what I am hearing from my contractor regarding gapping caused by humidity contraction. He’s saying that I could see as much as a 1/4″ occurrence. Is it possible to alleviate that potential with a moisture barrier and/or can you help with any other solutions to my dilemma? how well would a dehumidifier work? I do not want engineered or laminate flooring.

  25. Loft and Insulation says:

    Wow. This is impressive. Thank you.

  26. ridebiler says:

    Loving the information on this site, you have done great job on the content.

  27. Joanne says:

    I have timber floor boards that have a Gemini finish. For 15 years they have been great. We have resealed with this type of finish a few times over the years in the high traffic areas. In the last 6 months ( no reseal has been done for over a year) the dining chairs have been leaving circle marks on the floor where the leg sits. Every time we move the chairs, sit and reput back under the table a new mark appears. I changed the protectors underneath each leg as I thought they were worn but now have more marks. I’m so disappointed as our floors are our pride and joy. Any advice would be appreciated. Thank you

  28. Maria Cole says:

    I live in a mobile home. The floor in the master bedroom is bulging everywhere but nly when the heat is on and when the heat goes off the bulging goes down?

  29. Paul says:

    I’m having a solid oak wood floor installed (unfinished white oak 2-1/4″) onto a plywood sub floor. The installer is laying down a moisture barrier prior to installation, but I have my doubts that it is effective enough, knowing that the oak flooring has relief channels milled out on the underside and having a basic understanding on how moisture transports through air. I’m paying a premium, and want this job done as optimally as possible.

    I have noticed that some pre-finished solid oak planks are sealed all of the way around, and some only top and bottom. Would there be a benefit of sealing the underside of the unfinished solid oak planks before installation to increase the stability during RH changes?

    Would only sealing the top and bottom of the planks (and not the tongue and grooves) only this increase the chances of cupping due to the only moisture absorption avenue being though the tongue and grooves?

    We are adding to match an existing floor, which is displaying some slight crowning, but it is unknown if this crowning is due to sanding previously cupped boards or due to a moisture imbalance.

    Does the answer change if I am considering installing radiant heating beneath the floor (from below) in the future?

    Thank you in advance for your answer and for the wealth of information you have provided here.

    • Jason Wright says:


      Congratulations on the new floor. Your question regarding the sealing all the way around the plank is better answered by the factory. A lot of factories do this differently and it’s based on how they are drying the wood prior to milling it. With regard to your questions on the moisture and the radiant heat, I would defer you to NWFA.org. There you will find all the answers regarding hardwood, moisture, concerns, and issues, etc.

      Hope this helps, thank you for writing in.

  30. Mirush says:

    Oh man, great info here!

    I went with a local restoration company and was very unhappy.

  31. Andrea says:

    This is very informative suggestion. It this is a very helpful post. Thank you for the post.

  32. Paula Woolley says:

    Our home was built in 1980 and has Parquet floors that has carpet over them. Aug 2019 we pulled them up and found these beautiful floors. We had them stripped and refinished and they are beautiful. Last night walking through the living room I noticed a HUGE warm area. We googled it and saw many sites saying a slab leak. We made sure all water was off and checked the meter, nothing!! It was not moving whatsoever, we watched for several minutes! What else can it be? the HUGE warm area is still here!

    Thank you in advance for any advice!

  33. Amy says:

    Hi, we moved into a 1950s house this summer in the UK and there was hardwood parquet flooring in 3 adjoining rooms downstairs. We redid the kitchen and took up the floor to lay tiles instead. Whilst doing this a ridge appeared in the flooring in the room next to it. This has now spread, and we have the floor lifting in both that room and the third room.

    Could we have disturbed it when we took up the parquet in the kitchen? Is it likely that this is happening because we have not had the heating on as much as the previous owner (was an older lady, retired, spending all day at home whereas we go out to work/don’t have the heating on all day)? We did also once mop the entire floor as it was dusty and horrible through all three rooms due to the kitchen revamp.

    Underneath the wood there is a layer of a bitumen type substance which doesn’t appear that sticky when pieces have popped out and then, based upon the removal in the kitchen, a concrete screed.

    Any advice much appreciated as we’re not sure what is going on.

    • Jason Wright says:


      Thank you for writing in. There could be a couple things going on. Depending on your location and its Relative Humidity (RH), and the temperature change could cause the floor to react and move. Wood is hygroscopic so when moisture can absorb into wood it will. When it releases, it shrinks. I hope this is helpful.

  34. B says:

    I need to find an independent evaluation for my flooring. Three weeks after installation it has developed checking. The flooring was evaluated by a person that the company sent out. He said too much humidity in the home. I live in San Diego, away from the beach. This is an arid climate. No moisture in the flooring at all. I have had Hartco engineered flooring for 20 years never checking and Mirage engineered wood flooring12 years and they never had checking. I find this to be an unreasonable decision considering the past wood floors.

  35. Imelda says:

    Can hollow wood floor cause the floor to warp? When I first moved in, I detected several hollow sound floor and some darker patches. Now majority of the floor has warped up, so badly that I can’t close the door. I was told that the floor warp is due to moisture and not due to waterproofing failure. I’m wondering whether hollow floor can mean that it’s poor installation and which then contribute to the floor warp. Appreciate any input.

  36. Hugo Lee says:

    Help. I had my second floor bedroom done in pretreated hickory a couple of years ago. No signs of cracking or cupping or separation. At night, mainly during the spring or fall the floors pop real loud over the entire room. Sounds like gunshots and woke us both up in a moment of terror. Thought the floor was ripping itself up. When I turn on the lights there is no evidence of changes or plank movement. It can be real scared and there has to be something wrong.
    Any ideas or suggestions for help would be greatly appreciated.

  37. Jodi oelkers says:

    I hv an old house that has wood floors only in the 3 bedrooms and the front room can I clean the cracks out real good and seal them up with polyurethane? The house is a 1927

    • Jason Wright says:


      Thanks for writing in. Seasonal changes are common for 3/4″ solid strip wood. You can clean the cracks and apply urethane, but the seasonal changes will still go through a process that makes it gap seasonally.
      There isn’t anything that can be done to stop this other than float a new floor over it.

  38. Thomas Clarence says:

    It would never have occurred to me that hardwood floors can expand by absorbing moisture from the air. I recently noticed the wood floors in my kitchen have been making a lot of creaking sounds, and some of it is starting to lose its color. I guess this could mean that it has been absorbing a lot of water. It seems like it would be a good idea for me to have my floors refinished.

  39. Twocare Home Services says:

    Nice blog. Thanks for sharing this with us.

  40. Mark says:

    I am wanting to install real hardwood flooring over my wood sub-floor. What i have for a sub-floor is 1/2″ plywood then 15lb felt then 5/8″ plywood. I also have 6″ bat insulation on bottom being held up with chicken wire. i live in South East Texas it gets hot here so a/c runs a lot. Do i need a vapor barrier? i was also thinking of removing the bat insulation and replace it with close cell foam. Please advise what to do.

    • Jason Spangler says:


      Thanks for the questions. I would recommend that you contact the National Wood Flooring Association at http://www.woodfloors.org/ They are the organization that pretty much writes the installation standards for wood floors. They will point you in the correct direction. Good luck.

  41. Tom says:

    Hello Jason – my contractor did a great job refinishing our wood floors. Unfortunately I inadvertently left a microfiber mob with an attached liquid cleaner dispenser on the floor and several hours later most of the bottle drained into a puddle about 18″ x 24″. I wiped it quickly and although there is no staining, the floorboards are now somewhat wavy. The refinishing was only done about 8 weeks ago. My contractor said he would likely have to replace the warped boards which I understand, but he wants to refinish the entire room. Is that really necessary, given the job is practically brand new? I would think they could match rather easily. It’s also in an area that is not terribly conspicuous. Thanks.

  42. SUSAN says:

    Hi. Jason, Just antes you to know what a great job of giving advice to everyone regarding wood flooring issues! I grew up hearing most everything you have written but thoroughly enjoyed reading your blog!
    My great-grandfather, grandfather, father, uncles, husband, and son are in this business or have been. My husband and I are in the process of building our last home. We just had 5 inch white Oak flooring installed. For the stain we chose Duracell oil based stain in the color Aged Barrel & Satin poly finish. Trying to avoid moisture problems, we made sure the heat/air unit was running. There is a Basement Below that we keep a dehumidifier running all the time to keep the moisture below a certain level. Our floor installer did a wonderful job for us since we are now too old to do it ourselves. Keeping our fingers crossed that everything stays flat and doesn’t cup since we are having a great deal of rain right now in Tennessee. Thanks again for giving such good advice & Keep up the good work!

  43. Richard Cotter says:

    We had new 3/4 ” oak floors installed last June. The boards were acclimated for 2 months in the room they were installed in. We did 4 rooms, done by installers. The boards were not all laid at the same time, one room was done 3 months later. Right from day one the boards all seem to be cupped a bit. enough so that you can feel the board edges when you walk on it. If we drag our feet across the floor we can feel the lift on all the boards. Do you think this could be caused in manufacture? The installers seemed very well experienced.

  44. I like what you said about high humidity possibly damaging your hardwood floors. My wife and I would like to get some hardwood floors installed. We’ll be sure to look further into our options for avoiding humidity after we have them.

  45. Tyson Coolidge says:

    It’s good to know that high humidity can damage your hardwood floor. My wife and I would like to get some hardwood floors for our home. We’ll be sure to look into our options for keeping the humidity low to keep them in good shape.

  46. Tanya Meyer says:

    Hi Jason,
    Im having an issue with my engineered wood floors, which were installed in my condo almost 5 years ago, on top of the original cement floors ( which were already 20 years old. ) Up until recently, my eng.wood floors looked great, with a smooth surface, and sat perfectly flat and solid onto of the cement. Suddenly, yesterday morning, i noticed a bulge near the kitchen and when i stepped on it, heard water squishing around under the surface. Clearly water is trapped under the flor, which is glued tightly together. I did not spill anything on it…and have investigated all the appliances which could potentially be leaking, but cannot find any source of moisture from fridge, dishwasher, sink, etc. ( the wood is installed throughout the condo, including the kitchen; only the bathroom is tiled with stone. ) The only explanation i can think of is; there is a repair job going on outside my front door, where a big concrete deck that was leaking into the condos below it was jackhammered off, and is in the process of repair; the day before the water started collecting under my floor was the day they tested the repair job outside; the contractors w poured large volumes of water into the repaired hole ( about 4 meters x 3 meters, and let it sit there for hours, waiting to see if it would leak into the condos below. Once they were satisfied it wasn’t leaking, they sucked the water out of the hole and are still working on replacing the cement. Could it be possible that the water from the repair job made its way 9-10 meters across the deck and into my floor under the wood? I need to figure out where the water is coming from but cannot see anything obvious. Please let me know if that seems like a possibility or not, thanks.

    • Jason Spangler says:


      Thanks for the question. I am having a hard time visualizing the repair work and fault testing you are describing on the deck. That being said, it is WAY too coincidental that you had no problems until then. The water won’t travel laterally IN the concrete, but I am wondering if somehow it is traveling on top of and under your floor. The best way to verify is to have a qualified flooring inspector come out and evaluate the situation. Good luck.

  47. Thomas Jameson says:

    It’s good to know that boards can shrink and create unappealing space when heated in the winter time. My wife and I are working on building a new house, and we want to make sure that the floor stays in good condition for as long as possible. We’ll be sure to look into our options for engineered floors to accomplish this.

  48. Tricia says:

    My hardwood floors are buckling and its only been two years since they were installed in new construction on a concrete slap. When they were first installed, before I closed on the property, they buckled badly and the flooring company fixed it, but its been buckling in same spot for a while again. I don’t think they let the floor acclimate to the house before installed. They are real hardwood and are glued together in a floating floor system. . The floor guy told me I had to keep my air conditioner fan on auto 24/7, get a dehumidifier to run 24/7 and keep the air set on 70-74. I find this to be quite annoying that I have to do this and not be able to open my windows or keep my air set higher, since that is where I am comfortable. Is he just making excuses or is this what I have to do forever? Why didn’t someone tell me the requirements before I purchased the floors? I am really at a loss on what to do.

    • Jason Spangler says:


      Thanks for the questions. The National Wood Flooring Association recommends ambient conditions be “As a general rule, wood floors will perform best when the interior environment is controlled to stay within a relative humidity range of 30 percent to 50 percent, and a temperature range of 60 degrees to 80 degrees Fahrenheit, but optimal conditions will vary in different regions based on average moisture content and RH”. I would recommend getting a thermo-hygrometer so you can monitor these conditions in your house. This may allow you to make things more comfortable to your taste. As for the floor buckling, I find it interesting that it is buckling in the same spot as before. I would look for a certified wood flooring inspector in your area and have them evaluate the situation. You should be able to find one on NWFA.org.

  49. Jaya says:

    Hello JAson,

    We recently installed hard wood floors throughout our house. We live in chicago and had water damage in the house due to pipe burst and then we had the hard wood floors installed last Oct. This Jan we started noticing gaps between the boards. The gaps are able to fit a dime in some areas and some are less gaps than that. But there are gaps all over the house. The humidity level I checked is 30%.
    we have 2 furnaces and 2 humidifiers. We have hardwood in the 2nd floor and 1st floor. This is a newer house with just 7-8 yrs old
    When I contacted the wood guy who installed the floors he says to get a floor inspector to see why this is happening. Is it installation issue or humidity issue.

    I am very concerned. Where can I send you a pic of the floor. Any help or suggestions is appreciated

    • Jason Spangler says:


      Thanks for the questions and I am sorry about the floor. Most wood floors are going to have a specification for humidity levels of 30-50% so your measurement is on the low end. The gapping tells me that the wood has shrunk, after installation, and may be caused by the low humidity. I would also recommend that you have an inspector come out and look at the floor to determine the potential cause. You can find one at http://www.nwfa.org Good luck.


  50. Chris Clark says:

    Thank you for the reply. Apologies for the confusion. The wood floors are on the main level. I only included the basement pour date as a matter of reference. I have contacted an inspector who thinks he can help. We are trying to determine if this step and expense will truly help us – not sure what weight an inspection will carry.

  51. Chris Clark says:

    and of course then also correct: AC unit was installed but it was between 4/30 and 6/20 should be 5/30 and 6/20.

  52. Chris Clark says:

    correction Fast Fwd date is 5/30 not 4/30… typo.

  53. Chris Clark says:

    We had a home built in 2018. Our basement floor was poured on 3/20/18. Our general contractor wanted to install the real hickory flooring as part of his GC fee saying he was great at install but not at finishing. We happened to have a good friend who had installed and finished several hickory floors and was willing to do the finishing for us. Or GC was fine with this plan rather than hiring a subcontractor to do the work. We made sure the exact wood was ordered by our general contractor that our friend recommended from the vendor our friend recommended. The wood was delivered on 4/20/18. Our general contractor installed it between 4/23-26. Our GC claimed he checked Moisture Content prior to install (where, what, how and how many places we have no idea). It looked great. Our friend came to sand, seal and finish coat it for us between 5/8-11. He mentioned a couple places in the last row of boards where the boards were just set in place… not glued or nailed. When our GC said he couldn’t get to the house to fix the boards, our friend did it so he could continue his work. It looked absolutely gorgeous when done. After a couple days to dry thoroughly, the GC covered the majority of the flooring with paper to protect it while other subcontractors were doing their work… plumbers, electricians, HVAC, stone mason, carpet, finish carpentry, cabinets, ceramic tile, etc.

    Fast forward to 4/30/18. We got a call from our GC that the floor near a window in the den was bubbling… better description is buckling but that was the word he used. Three or four rows of the wood was lifting up away from the floor and you could feel it under your feet. This was noticed in an area that wasn’t covered by paper. There was no evidence of water on the floor or the window. They proceeded to walk over the rest of the floor still paper covered and found no additional problems. After much deliberation by our GC and blame being pushed on our friend for not finishing the floor right, the GC had his finishing sub top nail (nails through the top of the wood planks) the affected area. Our friend that did the finishing claimed it had to be due to improper installation. Causing us to be stuck between the two with no true resolution.

    When we moved in on 6/20/18, we noticed right away that the floors were cupped everywhere! And in a few places along the edges of doorways to other rooms with tile (even though the final tile trim pieces between the two floors had not been completed yet) there was crowning. Our GC still blames our friend for finishing the floor wrong, and at one point said “Well in 5 years when your dog is gone you can have it totally redone.” Over the winter the cupping and crowning has reduced and some boards are now showing 1/8″-1/4″ cracks between planks. The den floor boards that had buckled are flatter but don’t feel right when you step on them.

    Between the installation and our moving in, the new build did not have an air conditioner yet. There was a small humidifier (ours) running non-stop in the basement, but the weather took a very hot and humid turn with almost daily rains and temps between 85-95F degrees. During this time of high temp and humidity sub contractors were in and out of the house constantly leaving doors and windows open on both levels of the home. I cannot find my note regarding when the AC unit was installed but it was between 4/30 and 6/20 – I think mid May but would need to dig more to find the exact date. Could this heat and humidity have caused the problem, thereby being a GC responsibility?

    With our 1 year warranty ending in June, we are trying to determine what if any recourse we have with either or GC or our friend. If a professional determined our friend was at fault, we are 100% certain he would make good on it. And if a professional determined the GC was at fault, we think he would kicking and screaming make good on it.

    Really appreciate any input, guidance, etc. you can offer. THANK YOU!

    • Jason Spangler says:


      Thanks for the questions and sorry you are having the issues. For sure it can be stated that there is a difference in the moisture content of the wood between install and now. Whether that is due to incorrect acclimation of the product, installation practices, or changes in the ambient conditions, it’s hard to know without actual information from prior to the installation to now. You would probably be best served to have a hardwood flooring inspector come out and evaluate the situation. You may want to start here http://www.nwfa.org One potential issue I see from the very beginning, if I am understanding the flooring product correctly, is the fact that most solid wood flooring manufacturers don’t recommend installing ¾” solid flooring in a basement application. Good luck.


  54. Jason, I installed bamboo wood in three of the bedrooms, they look great. But in one of the rooms a dark spot was on one of the panels. I thought one of the kids spilled something on it. Now nine months later the spot has gotten bigger and is on three panels, it feels cold and damp to the touch. Is not near a window or the door. But the room if near the in ground pool. Not sure if the damp feeling is because is near the pool. The other room is near the pool to and is find. I’m ready to replace the panels but what can I do to avoid it from happening again? Thank you for any Advice you can give me.

    • Jason Spangler says:


      Thanks for the question. Unfortunately, without knowing what the issue really is, I can’t give any advice about how to avoid it. You may want to have a certified inspector come out and evaluate the situation to determine the cause. You can find one at http://www.nwfa.org Good luck.

  55. Tim Yaotome says:

    Since you mentioned that heated homes in winter can cause one’s hardwood floors to shrink and spaces to appear between the boards, it reminded me of my own bedroom. The floor is made up of hardwood there and I turn up the heater before I go to sleep during the colder months of the year. As I am now aware that this can reduce their durability, I will find a professional to inspect all my hardwood floors. This will not only help keep my house warm and safe but also know whether they needed to be replaced and refinished before the first snow falls.

  56. Rob Hogue says:

    We have hardwood floors in our 10-year old house, and over the last month or two (quite wet here) some of the boards seem to pushing up the string or glue in between them (it’s extruding). I bought a hygrometer and the humidity is about 55% inside and about 60% in the crawl space (which is insulated but maybe not moisture barriered). Any thoughts / help greatly appreciated.

  57. Scott Viator says:

    Jason, we installed antique pin floors 3 years ago on our slab and on wood subfloor upstairs. The floors on the first floor installed on the concrete are fine and perfect. After 3 years from installation date the wood floors upstairs on the wooden subfloor they started to cup and buckled in both rooms mostly in the middle of the room. The two upstairs rooms have a unconditioned double garage below them. The hall way that runs along the entrance of the two rooms had the original antique pin floor. Both rooms had carpet in them when we purchased the home and we pulled carpet out upstairs and down stairs. The only place we are seeing the cupping and bulging is in the bed rooms upstairs. The contractor laid a felt between the wood subfloor and the antique pin floor. I’m not seeing any areas of moisture damage on the wooden subfloor plus the original hallway wood floor has no issues and it is over the unconditioned garage. Looks like the original floor installer left enough space along the edge of the walls to expand. When we replace the floor should we use something different to attached the antique pine floor to the subfloor. Again, originally it had a felt beneath floor and was nailed to the wooden subfloor. Would like to make sure it does not happen again. What should the application be.

    Notes: Home is in Lafayette Louisiana and not in a flood zone. When we pulled the antique pine board up the moisture reading was 6%. We just can’t firm up where the moisture came from. No noticeable moisture damage to the wood subfloor.

    Your thoughts!

    • Jason Spangler says:


      Thanks for the comment. This very well could have been an acclimation issue. You say the pin floor you took out was 6%MC, which is very low, telling me the conditions in your house must be kept very dry. I have a hard time believing in LA that wood floors are stored in 6%MC environments prior to installation, it probably much higher due to the natural ambient humidity. If that were the case, it may take a bit for the new floor to acclimate to the dry conditions in your house, else I may cup after installation. This is strictly a theory. As far as the installation process, I would refer you to the National Wood Flooring Association at NWFA.org. They have specific guidelines for installation practices. Good luck.



  58. Sam Li says:

    I like what you said about treating the subfloors the right way and accurately measuring the moisture. I think that hiring a professional installation service is the best way to make sure the flooring is installed correctly and that the subfloors are being treated as they should be. My wife wants to install hardwood in our kitchen, so we’ll be sure to contact a reputable flooring service in our community to get the job done right.

  59. Nannie E. Carper says:

    Dear Jason,
    I bought my home 2 years ago June 2016. My neighbors told me the owner had put new hand scraped wood floors in the living room in 2015 . This year I started noticing black bubbles on 2 boards in front of the windows now it is 6 boards .I clear caulked the windows just in case no bulking or popping up no one has ever seen anything like it that has seen it . It is really worring me . I found one picture online that it looks like but no explantation. I had one floor man look at it he wanted $500 to take up a few boards I didn’t feel comfortable with him he had never seen it before .So I didn’t tear the floor up . I wish I could send you a picture .Help is all I can say
    Thank you,
    N. Carper

    • Jason Spangler says:


      Thanks for the question. I would contact the National Wood Flooring Association at http://www.nwfa.org and find a certified flooring inspector in your area to look at this floor and diagnose the issue. Good luck.



  60. Robert says:

    We recently bought and remodeled a home that was built in 1982. The house is built on a concrete floor . We changed most of the sub floors. We installed 3 inch oak flooring in all rooms except bedrooms and master bath.
    The floor has been down about 10 months. I have noticed that the floor is cupping consistently throughout the house . There is one exception. We have a converted sun room that is not on concrete. That room has not cupped.
    This was an unusually humid summer in Cape Cod. I’m hoping when the heat comes on in winter that the floors will evenout. Do cupped floors smooth out when the humidity drops?


    Bob Caplan

    • Jason Spangler says:


      Thanks for the question. Depending on the severity of the cupping, the floors may return to normal, or close to it. If this is the case, I would make arrangements to add some type of dehumidification system to your house to keep it from happening again. Good luck.


  61. Darlene says:

    Hi, my 3/16” red oak flooring was installed, sanded, stained, and coated with polyurethane in May. Today it buckled! I wasn’t happy the contractor used flakeboard as the subfloor. Could this have caused the problem??? Here’s some facts: kitchen floor, humidity maintained with A/C, no leaks or spills.

    Thank you!

    • Jason Spangler says:


      Thanks for the question. I would direct your question to the National Wood Flooring Association, http://www.nwfa.org, regarding the installation on “flakeboard”. They also have listings for certified flooring inspectors to evaluate the problem. You talk about a lot of the internal issue that cause buckling problems, but one area that many ignore is the area within the crawl space. It has the potential to cause a major issue. Good luck.


  62. Agnes Richmond says:

    We had our hardwoods sanded and restained about five years ago. They are solid hardwoods and the majority of the floor is a wood subfloor except for about two feet which is a concrete slab. This is a part of the garage concrete slab that extends into the kitchen. (Don’t know why the builder did that.) Two things are going on. Where the concrete slab meets the subfloor in the kitchen, about a foot of the flooring is bowed up about two inches. You can trip on it if you’re not careful.

    The other problem is most of the wood is cupping. This did not happen before we sanded and restained our floors. Sometimes it is worse than other times. We have checked for water everywhere we can think of and don’t see anything. We live in Georgia and the humidity is very high in our area. Any thoughts on what could be causing all this and what we can do to fix it?

    Thank you,

    • Jason Spangler says:


      Thanks for the questions. Stating the obvious, but you obviously have a moisture imbalance in the wood floor. Many times this is caused by inconsistent relative humidity and temperature conditions either in the occupied space or in the crawlspace. Also, many times the crawlspace may also not be properly ventilated potentially causing an issue. Measuring conditions in both of these spaces, over time, would be a way to documents and determine consistent conditions are being maintained and that the conditions are appropriate for wood floors. Most of the time wood flooring should have occupied space conditions between 30-50% relative humidity to minimize cupping or crowning like you are seeing. From the statement you make, “Sometimes it is worse than other times” I would guess conditions are not consistent throughout the year. I would recommend having a qualified wood flooring inspector come out and help with the identification of potential issues.

  63. Amy Shaffer says:

    Jason. we have since found out that there was a major flood upstairs in the apt across the hall from the sprinkler system. It was suggested that we find a building inspector who will use a water meter to find the moisture level, etc. Thanks for your reply.

    Amy Shaffer

  64. Amy Shaffer says:

    Hi Jason,

    Our condo has engineered floor over concrete and is 10 years old. We have lived here 3 years without any problems. Last month in the entryway hall we started seeing some rippling, a couple of 3″ long , narrow bubbles, and a little bit of lifting where some of the board ends meet. We have had the AC checked (no problems), and there seems not to be any water leakage around our washing machine. The apartment next to ours had a toilet leak, but the only damage was to the unit directly below. We had 2 separate flooring contractors come in, one specialized in repairing floors and water damage and was NFWA certified. He said we should try to get the RH down (it was 50 – 60 % with constant AC) so we bought a small dehumidifier. I have read about repairing unglued sections by drilling a hole and injecting glue (the second floor person had never heard of that and although I emailed him the info, he never responded). Actually, both of them seemed more interested in selling us a new floor than repairing the old one We don’t know what to do anymore, other than vacating our unit for 6 weeks and spending $20,000 for a total new floor. I don’t even have an idea of what kind of person to contact – someone who does renovation? We would really appreciate it if you could shed some light on this and suggest someone to turn to.

    Thank you so much!

    • Jason Spangler says:


      Thanks for the comment. I would continue to seek out a qualified flooring contractor to do the repairs or have someone explain, in detail, why you need a completely new floor for isolated problems. Depending on the severity of the problems, the humidifier may help remedy them without any repairs. Either way, you will need to address the humidity in your house to ensure that the conditions stay consistently in the 30-50% RH, which is typically recommended for wood floors. If you need to identify additional qualified wood floor installers, you can find a listing at http://www.woodfloors.org. Good luck.

  65. Molly Bruce says:

    After having my oak floors refinished, I noticed that they looked “wavy” in a large area of the kitchen instead of flat. They were flat before sanding, stain, and clear coat. When I asked the flooring contractor about it, he said” Oh that’s just grain roll…you can’t do anything about that.” It’s common. I can’t find anything discussing Grain Roll on any floor refinishing discussion site. Was he feeding me a line? Thanks, Molly

    • Jason Spangler says:


      Thank you for the question. I can’t say that I have heard this specific term, but I would recommend you contact the National Wood Flooring Association, http://www.NWFA.org, and see if they have heard of this issue. Terms can sometimes be different and NWFA should be able to help if it is a true issue. Good luck.

  66. Loreen Griffis says:

    I have a 115 year old house. I bought 25 years ago. 15 years ago we put in double paned vinyl windows and siding and central. 10 years ago the kitchen had a fire and because of smoke we refinished the floors with polyeurethane. 3 years ago my floors started buckling terribly bad in summer. 3 inches in some spots. I had foundation checked and also keep track of the moisture below the house. Very dry under the house. The wood is also changing colors (white in color). What could be some causes/ solutions?

    • Jason Spangler says:


      Thanks for the question. Buckling means there is a moisture variance from top of board to bottom, with the bottom being dryer. This could be a maintenance issue or relative humidity variance inside or out, among other things. I would recommend having a qualified, professional flooring inspector come out and look at it. The National Wood Flooring Association has a listing of certified inspectors at woodfloors.org. Good luck.

  67. Sandy Cole says:

    We recently had 4” Engineered wood installed throughout our downstairs. Since the hardwood was installed which was about a month ago, the floor makes a crackling sound throughout and some places sound very hollow. Installer said he used glue around the perimeter and stapled everywhere else. Our previous floor was a Mirage flooring, and we never had any crackle sounds. This one is a diffent brand, and so far, very disappointed with the results. Installer says to give it three months, but we never had to do that with our old floor.

    Any help in why this could have happened or what the cause could be, would be greatly appreciated.
    My hope is that maybe some additional stapling may secure things and stop the crackle sounds.

    • Jason Spangler says:


      Thanks for the question. Different woods and different products react differently to their environments. There could be numerous possibilities to the causes and cures for this floor. Sometimes the best thing is to get an independent evaluation of what is going on. https://www.woodfloors.org/certified-professional-search.aspx is the consumer website for the National Wood Flooring Association. Here you can find a certified wood flooring inspector that should be able to evaluate your specific situation. Good luck.


  68. Sophia says:

    Hi Jason,
    we had burst water pipes in Winter, due to the extreme cold, could all the issues associated with that cause the floor boards to creak badly?
    It is rented as a Gite and now customers complain about the noise.
    It happened in the pipes between the ground and first floor ie ceiling of lounge and floor of upper level.

    • Jason Spangler says:


      Thanks for the question. If the wood absorbed the moisture/water from this and expanded, you may have a situation that causes symptoms of this nature.



  69. Nathan says:

    Renting an older house and had a pipe leak that previous tenant never made known that cause water to run to one corner of the house. Got to the point where water started to smell bad and could smell it indoors. Plumber fixed that and the smell went away but from what I’ve seen there are multiple spots in different rooms that have raised subfloors it seems. Rechecked that one corner after heavy rain and it accumulates water, not as much as with the leak but visible. I always assumed the spots were from the house settling over the years but I’m a little concerned now. Any advice or additional info I should know about?

    • Jason Spangler says:


      Thanks for the question. I would start with exterior drainage first. Are all of the gutters up, in good shape, and draining? Maybe there is a need to drain them further away from the house. If all of this looks functional, you may need to look at a sump pump in the low area of the house to keep the water out. Obviously, this is all based on issues like the leaky pipe are fixed. Good luck.



  70. Ginger says:

    Last fall we refinished our hard wood white oak floors, with water base finish they turned out beautiful. But after nine months I noticed the seems in some random areas coming up as if dried glue is pushing up between the boards. Could high moisture outside be the cause, we have had rain for two weeks? How do I protect them if this is it? Thank you..

    • Jason Spangler says:


      Thanks for the email. I would recommend having an NWFA Certified Inspector come out and evaluate the issue and give you some recommendations to remedy the situation. Their website is https://www.woodfloors.org/. Good luck.



  71. Thank you for your valuable resources keep share the information like this…

  72. farzana says:

    Hi my woodfloor was installed on December 2017 last week we change our boiler and some water has gone in my woodfloor now my woodfloor has pop up a little bit and can see gap its about 3 meters where the floor have pop up the rest is ok. im very worried now as my floor was very expensive what can I do pleaae help.

    • Jason Spangler says:


      Thanks for the question. If the water source is taken care of and the excess water is cleaned up, it might be best to keep the conditioned airspace consistent and see if the problem “fixes” itself. Worst case it doesn’t correct itself and you may have to have that section replace. Good luck.


  73. REL says:

    Help! We recently bought a new construction home (3 months ago). We had engineered hardwood installed. On the first (main) second (back bedroom), and third (master bedroom) floors, there are issues with the subfloor and leveling of beams which have resulted in raised bubbles and squeaking. While the GC suggested that we nail into the floor, independent flooring contractors have informed us that this is not a permanent solution and that the subfloor underneath needs to be examined and repaired (i.e., sanded down, planks replaced, etc.).

    On the second floor, the edge of the floor by the stairs is higher than the middle of the floor. This has resulted in a huge gap between planks. The floor needs to be removed, sanded down, and replaced. This will also affect the molding and stairnose transition molding.

    Also, the floors in the two guest bedrooms were installed incorrectly. There are nail holes and planks installed groove to groove, as opposed to tongue-and-groove. The empty nail holes can also be seen on the first and third floors.

    At this point, the developer and GC refuse to re-install the flooring. The bubbling has gotten progressively worse, despite some nail holes drilled in…

    At a loss for what to do…

    • Jason Spangler says:


      Thanks for the comment and I am sorry to hear about all of the issues you are having with your floor. I wish I had some easy fix. It sounds like there are a multitude of issues with the floor that require attention. I would visit http://www.woodfloors.org, the consumer website for the National Wood Flooring Association. Besides having a wealth of information, they also have a listing of certified wood flooring inspectors. Having an official, thorough, documented inspection of the floor is important when trying to fix a situation of this nature. This inspector may also be able to give some better insight into potential remedies, besides replacement, if there are any. Good luck.

  74. Sherri says:


    I have oak hardwood and there is an area in my living room that just a week ago is producing bubbling through the cracks. I feels like oil of some kind. It is in about a 3 foot by 3 foot section of the living room that is not near any water source. I have been here are 2 years and this is the first time its happened. But as I continued to clean the area and inspect it sometimes it is a puddle of what again appears to be an oil substance. This morning there were nickel size bubbles in the cracks of the same area.

    I have sprinkled baby powder over the area to absorb the moisture, and it appears to be crystallizing, for a lack of better words. The powder does seem to be pulling it out but I want to know if there is another solution? I have inspected every square inch of this 2700 sf. The entire 1st level is wood except for the master suite. There is nothing even close to this happening anywhere other that that one small area in the living room. It is not under a window and not even close to the Front Door.

    Any suggestions? Do you think it is oil – it has no odor and it is not water.


    • Jason Spangler says:


      Thanks for the question and I will be totally honest, I have not a clue. It may be best to contact a qualified installer or NWFA certified inspector for their input. Personally, I think I would want to have a professional pull the specific board in question and inspect the subfloor to determine if the “oil” is isolated in the board or coming from/through the subfloor. Doing this should help you determine whether additional remedial action is necessary. Good luck.


  75. blair says:

    this q&a is very helpful thank you
    I live in 10 year old condo with engineered oak? flooring. my washing machine was leaking for likely weeks or even months. did not realize until water started coming up through the floorboards in hallway nearby. dried as quickly as possible but cannot know duration of leak. the wood floors were slightly discolored with small gaps between few boards. I was not going to redo floors but the change in temp (or progression of rot mold) has caused further discoloration (grey along edges), larger and more gaps between the planks.
    is there chance I don’t have to tear out the floors? to risky?

    • Jason Spangler says:


      Thanks for the question. There is always a possibility. In my opinion, the best thing you could do is have a section of flooring pulled out and see exactly what the subfloor and/or backside of the flooring look like. This may show more to the extent of the damage. In this case, you may only have to repair the section pulled out. Good luck.


  76. Ade says:

    Red oak hardwood floors were installed throughout our newly constructed home (we moved in at the end of July 2017). The boards on the first floor began to contract in early December. Since the contraction took place, in the space between each board there is what looks like a beige stripe. The end result is unsightly (to put it mildly). We know an extra coat of polyurethane was applied on the first floor because a tradesman walked across a wet floor. The builder blames us saying we should have used a humidifier. Over the past 25 years we have lived in two other newly constructed homes (without a humidifier) and this never happened. Your thoughts and suggestions are greatly appreciated.

    • Jason Spangler says:


      Thanks for the comment. In your situation, there are two common causes. 1) The ambient conditions in the house weren’t controlled prior to or during installation. Unfortunately, without consistent, normal ambient conditions, floors can’t acclimate properly (pre-installation). The implication here is once they are installed and HVAC is on consistently, they acclimate to those conditions which could cause the floor to shrink or swell, depending on the change. 2) Everything was acclimated and installed properly, but ambient conditions weren’t maintained between NWFA recommended guidelines of 30-50% relative humidity. I would recommend finding an NWFA certified inspector to come out and evaluate the issue. Good luck.


  77. Liz T says:

    After purchasing our home, we noticed there were discoloration in the engineered hard wood floor spreading slowly over a course of a year. No one really knew what it was but I could smell mold/mildew. Sure enough, the flooring contractor, when tore up the flooring said it was dry rot and our carpet areas under the moisture barrier were also very wet in the living areas. The previous owner stated there was a slab leak but all the pipes had been relocated to the attic. We have sprinkler system only in from of the house and valve right at entrance. After cleaning and drying out the concrete and removing asbestos, the contractor then agreed to install our new engineer wood flooring. After about 3 months or so, we noticed a lot of crowning and bubbling effects throughout the areas of install. The entry way was most noticeable because the wood is starting to crack. The flooring company sent an independent flooring expert to see and he said it’s most likely moisture since his meter registered it and when tapped on the bubbling areas, they sound very hollow.
    The wood at in the garage during the waiting period and the installer used the moisture 4 in 1 barrier glue that was supposed to prevent moisture from coming up from the manufacturer of the wood, which was why we went thru with the installation. If we had cancel, they would’ve charged us 25% restocking fee. But now, it’s costing us a lot more.
    We still do not know where the moisture is coming from! There was not a lot of rain this past season, so it cannot be from the outside. We do live in a high water table area though, so we will be working on installing draining/French drains on our exterior soon.
    Any advice will really help us out. It’s going to be a very long process and costing us more than we thought. Thank you!

    • Jason Spangler says:


      First, thank you for the comments and I am incredibly sorry for all of the headaches you are encountering. I would try to get an independent evaluation of the issue you are having. One way to do that would be to go onto the National Wood Flooring Association website and find a certified inspector. I am not saying the flooring installer isn’t doing everything correctly, but it is always nice to have that independent perspective. Good luck.



  78. Takeyia Clay says:

    My hardwood floor in my hallway is becoming very lose and it’s off balance an appears as if it’s sinking an now it’s starting to become the same way in the living room just outside of the hallway what do you think the problem is and how can this be resolved

    • Jason Spangler says:


      Thanks for the comment. The best thing you could do is consult a local wood flooring installer in your area or contact the National Wood Flooring Association at NWFA.org to see if either can help with your specific situation.

  79. Sandra says:

    We have solid Brazilian teak floors installed in our new home 3 years ago. We had our crawlspace enclosed and they installed two dehumidifiers at the time. Over the last year we have noticed that our flooring is separating a lot in several places. Should we install a humidifer for the heated months? We have had several people work under the house to try and pull the flooring back together without luck.

    • Jason Spangler says:


      Thank you for the question. If I had to guess, it probably has as much to do with the environmental differences between the interior and the crawlspace as the crawlspace individually. I would attempt to find a qualified and certified wood flooring inspector that can evaluate this from a flooring specific perspective. Here is a website that may help: https://www.woodfloors.org/certified-professional-search.aspx

      Good luck.

  80. Paul Myers says:

    Hi, I had oak floor boards laid over underfloor heating 3 years ago, and everything has been fine until 6 months ago when three separate boards developed a brown stain, looking almost like a burn. There are no signs of leaks or distortion and the system works fine. Could this be due to the quality of the board or some other reason? We haven’t disturbed the system yet to look underneath! Thanks Paul

    • Jason Spangler says:


      Thanks for the comment. I would imagine there could be many issues. You state the observation that the spot almost looks like a “burn”. Are the three boards in the same area? It might be worth getting a cost-effective infrared thermometer and measuring the surface temperature of the floor in various areas for comparison purposes. Maybe higher temperatures in those areas, for whatever reason, is part of the issue. Prior to looking underneath, it may be worth looking on http://www.nwfa.org and finding a certified wood flooring inspector to evaluate and offer their opinion. Good luck.

      Thank you,


  81. Carol Botwinick says:

    Hi Jason,
    We have a home that we moved into about one year ago- The house is 58 years old and was in terrible shape-
    We bought the house already renovated so we don’t know much about what issues there may have been before renovation or how thorough the contractors were as this was a very quick flip.. There are wooden floors throughout the home and as of late I have been noticing 2 occurrences simultaneously in the kitchen mostly.
    1. Spacing between planks –
    2. Crowning- the centers appear higher then the sides-
    I read your articles on both these issues- The aspect of this that’s confusing is one might be due to dryness and the other might be due to moisture. Is there a cure or reason for these contradictory reactions that I might be able to investigate?
    I’d appreciate any insight or help that you might b e able to offer.
    Thanks so much,

    • Jason Spangler says:


      Thanks for the comment. You are correct, this seems odd to have both happening simultaneously. If this is a new floor, one potential culprit could be that some of the boards were wetter than they should have been at the time of installation, so as they acclimated to the room conditions, after installation, they shrank. In the same breath, some of the boards may have been drier than they should have during installation and as they acclimated, absorbing moisture from the air, they grew, causing the crowning. To get verification of this, I would contact http://www.NWFA.org and try to find a certified wood flooring inspector in your area.

      Good luck.


  82. Tom Bourdage says:

    We have red oak hardwood floors that were professionally sanded and re- finished about two years ago. The floor have been showing small cracking on the surface. We have only used the recommended cleaner the professional recommended. The surface cracking seems to be limited to the finish and the wood still looks good. Any thoughts on removing the cracking finish short of sanding and reapplying the stain and sealer? Can it be buffed out and resealed? Thanks for your help.

    • Jason Spangler says:


      Thanks for the comment/question. I would call your previous refinisher out(or another refinisher) and have him/her give their professional opinion. Depending on the severity and cause of the issue, buffing may be an option. In any case, your original professional should be able to take care of it appropriately.



  83. Nancy Burns says:

    I have off white, gray tones bamboo prefinished flooring. In the Laundrey room where the dogs drink and eat ,water has damaged some of the flooring causing it to torn blue around edges on several pieces. We just got new puppy and he potty on potty pad that must have leeked under his crate. The floor turned yellow with blue around the edges. Where is the blue coming from? Is there anyway to fix it! It’s in the cracks and about 1/4 inch on each piece of wood?Thank you, Nancy

    • Jason Spangler says:


      Thanks for the comment. Honestly, I haven’t ever seen or heard of blue around the edges. It sounds like it might have something to do with the liquid and its interaction with the finish or a cleaning product you use. I would contact a flooring professional to give you an opinion.



  84. Jeanette Calmette says:

    Hello. We could sure use some advice. We have called in a flooring person, our termite serviceman, and a plumber and they have all been unable to identify the problem. We live in southern California, have lived in our house 37 years and have never had any flooring problems until the last couple of months. So far, we have only identified three boards with problems, but we fear much worse if the problem is not identified and corrected. We first noticed the problem when the swiffer caught on a small 2 inch section of slightly raised board in our living room. The affected area is along one edge of the board about half-way down the length (which is only 20 inches long). It gradually became wavy with part of it raising up slightly and part of it sinking slightly and has now grown to about 5 inches long. Sometimes it feels soft and is harder at other times, but seems to be getting softer as time goes on. A second board about 1 1/2 feet away now has a raised bubble-like area about three inches long in the middle of a board. The third board is in our bedroom where the floor was damaged a long time ago. It now seems somewhat soft and never did in the past. No one can identify the problem. We had the subfloor area insulated in February 2010 with R-19 unfaced fiberglass batt insulation and have had a lot more creaking in the floor since then. I don’t know if this could be related or not. The weather seems to affect it as well. When the air is drier, it seems harder and vice versa. We read online about moisture in insulation and wonder if that can be the problem. There is no vapor barrier on the dirt floor of our crawl space. This house was built in 1953 and the previous owners never had one and we haven’t either. We’ve checked with our neighbors who have the same raised foundation and red oak hardwood floors and no one else has a vapor barrier either and have had no problems. Any advice would be GREATLY appreciated.
    Thank you,

    • Jason Spangler says:


      Thank you for the comment. My best suggestion for you is to contact the National Wood Flooring Association at NWFA.ORG and find a certified wood flooring inspector in your area. Having them come out and do an evaluation should help to identify potential problems.



  85. Adelaide Goodeve says:


    Really interesting blog.

    We have just had V4 engineered wood installed in our kitchen.

    It moves and cracks very obviously in places when you walk onto it.

    Could this be a moisture problem?

    Should all floorers always measure the level of moisture before laying the floor?

    Thank you


    • Jason Spangler says:


      Thanks for the comment. The movement and noises could be moisture, a subfloor that isn’t acceptably flat, etc. You would need to look for guidance from the flooring manufacturer on what is acceptable in your specific instance, but most of the time you would expect to see subfloor moisture testing and finished flooring moisture testing, prior to installation. Most of the time, documentation of this is required if there were to ever be a warranty claim. I hope this helps.


  86. Irene Rollins-Huell says:

    Hello I have hard wooden floors, I had the toilet tank to burst and spread water throughout the house, however the water evaporated quickly through the flooring, about 4yrs later there’s an unusual smell in the house. What could the smell be coming from. I am thinking mold from the moisture through the flooring?

    • Jason Spangler says:


      Thanks for the question. I have a hard time believing that it would take 4 years for mold to develop from an event of this type. Not saying it’s not possible, just seems unlikely. In any event, there would have had to be something else that had changed, environmentally, to aid the mold growth this far down the road. You may need to have a flooring inspector and/or an air quality agent attempt to diagnose further.



  87. Elizabeth Collins says:

    Hi Terry,

    What is the source of moisture coming into our Family Room? The French doors and back door or up from the unfinished basement?

    The room is 25′ x 25′ and the moisture reading in 12/13 in a 8′ x 8′ toward the French/back doors.

    What remedy do you recommend?

    Thank you very much,

  88. Terry says:

    hello terry .i had hardwoods in my house for 50 years but when we had them removed and new put down we fount there were problems from the old ac which cause damange where air vents where also the ac would make alot of moister i live at the coast .now i have new ac and new floors but in the crawl space there seems to be alot of moister what should i do is it because of the ac not seal tight or is that i need moister barriers?
    help ..

    Thanks Terry

    • Jason Spangler says:


      Thanks for the comment. My guess would be that this is more about a lack of vapor retarder and possibly not enough ventilation in the crawl space. The NWFA (NWFA.org) is a great resource and they should be able to help quantify how much ventilation is recommended and, if necessary, they can give you a list of wood flooring inspectors that may be able to help with additional solutions. I hope this helps.


  89. Margrette Willis says:

    Hello, had real hardwood floors placed in open living room, dining room, foyer and den December 2016. Contractor sanded the floors, all seams were smooth and you couldn’t feel where one begin and ended. After several months, you can feel that some of the seams have lifted a little, and you can also feel it when you run your fingers across the floor, walk bare feet and slide the swiffer across the floor (a bumpy feeling). When you look across the room, it has the appearance of some of them rising even those some of still flat. We have a crawl basement, the contractor suggested we place a coverings over the entire area, he hasn’t done that yet. We paid too much money for our floor and I absolutely love them but don’t want them looking ugly. Concerned as to whether or not the problem is inside the house or underneath. Should have the covering in the crawl space underneath the house done in about 2 weeks.Thanks for any suggestions. I waited 30 years to get these beautiful floors and now this.

    • Jason Spangler says:


      Thank you for the question. My best recommendation for you would be to find a qualified wood flooring inspector to come out and give their opinion. Most have seen various situations, multiple times, so it would be easier for them to give you viable solutions based on your specific situation. You may want to start at NWFA.org for a list of inspectors. Best of luck.



  90. spencer smith says:

    I have a question , my apartment ceiling had a huge water pipe break and it hit the floor which is parquet and it buckeled from my bedroom door to the middle of my living room is it safe to have my furniture on it? i do not know how if its glued together or anything else and neither does she.

    • Jason Spangler says:

      Hi Spencer,

      I’d recommend that you find a local inspector or restoration professional to look into it.

  91. Kathy says:

    I am sick over what is happening here – we discovered water running from underneath the baseboard in a bathroom – then discovered that our floors were hot in the living room under our very expensive hand scraped hard wood floors. We have over 2,000 feet of this flooring. Water was then leaking to the outside of the house to our patio. Our house is on a slab. We have all of the water turned off and a slab specialist is coming out today. Some of the planks are buckling a small amount already. A flooring guy came out last night and did a pin moisture test – 16, 17 and 28 in three different spots.

    What can we expect to happen to our floors. Coincidentally we just had our kitchen counters replaced along with faucets and sink. As the biggest concentration of moisture is next to the kitchen bar where the plumbing is, I am wondering if maybe they broke a pipe.

    I am not sure if you can recommend anyone to help fix/replace these floors. My husband and I are both really really upset over this. The reason we bought the house was for the floors. They are gorgeous.

    I am making myself feel better just writing to you. The flooring guy said to replace the damaged area and resend and stain the whole house would take over three weeks and we would have to leave….

    Please write back.

    • Jason Spangler says:


      Thanks for the email and I am truly sorry for the issues you are having. Depending on the amount of water, you can expect that the wood in the affected areas will grow, causing individual floor planks to exhibit various degrees of crowning. If it was me, I would first have a remediation company (Servepro, ServiceMaster, Belfor, etc.) come out and survey the damage and see what they would recommend to get the area back to pre-disaster status. Usually, once this is done (if anything is needed from them) you can then proceed to put things back together. The area(s) under the affected floor needs to be dried before you think about fixing the floors (in my opinion), this is what a remediation company can accomplish for you. Once you have this, if you aren’t comfortable with the flooring contractor you have been talking with, then I would contact the NWFA (National Wood Flooring Association) at NWFA.org and get some referrals for certified installers in your area. I hope this helps.

      Jason Spangler

  92. Karin says:

    We have a wood floor that has been installed over 4 years ago. We have never had a problem. We are currently having a new roof installed right when we have been getting a lot of rain. All of a sudden an area in my living room is crowning. Could the two be related????

    • Jason Spangler says:

      Thanks for the question. This is possible, but without knowing what the ambient environmental conditions (RH% and temp) were prior to the work and comparing them to what they are like now, it’s hard to say. I would contact http://www.nwfa.org and have a certified inspector out to definitively identify the issue(s). Also, if this is the problem, the problem MAY remedy itself once the environment is reestablish to its existing condition. Hard to say.

      I hope this helps.

  93. Ruth glenn says:

    I have a home build in 1968
    Well kept but the cracking and popping in my bedroom and hall l’m 85 yrs old and its. really scarring when someone walk when l’m sleeping ,its hardwoods laid concert laid can you please help me

    • Jason Spangler says:

      Ruth, thank you for the comment. I would contact a trusted, local flooring retailer in your area and have them look at your individual situation. If this avenue doesn’t work, I would recommend you go to http://www.nwfa.org and see if they can recommend a certified inspector that can come out and give you some guidance. Good luck.

  94. Francis Tremblay says:

    My floors are cracking and spitting all over my house . I had laid down pile and stick flooring throw out my home and now after time l have noticed large cracks all over the place hall ways bed room and in the kitchen . What would be causing such a problem throw out my home . I am not sure how to add pictures but if you need them l can send to you so that you can see to for your self what l am talking about.

    • Jason Spangler says:


      Thanks for the question. This may be answered, best, with a phone call. You may contact me at 800-634-9961 X235.

      Jason Spangler

  95. Chris says:

    I had a company install solid Jatoba hardwood floors. It was clear that they did not seem to know how to install the very hard wood and put pressure on some corners and created a split. We had them try to repair, but that was worse. My biggest concern is that the floor are uneven even though the subfloors were screwed down and in good shape, the wood seems to be ‘rolling’ some boards are higher than others and the floors are squeaky. Can I do anything beyond replacing? It was very expensive and the wood covers 90% of the first floor of the house. We have tried monitoring the ambient moisture, but in winter it’s hard not to fall down in moisture. Any suggestions would be welcome. It’s sad because the floors looked awesome for about a month (barring the cracks).


    • Jason Spangler says:


      Thanks for the question. This may be answered, best, with a phone call. You may contact me at 800-634-9961 X235.

      Jason Spangler

  96. Andrea M Devery says:

    We installed Morning Star Bamboo in our living rooms and kitchen. We removed old sub flooring and replaced with new thicker sub flooring. We used a high quality pad/water vapor recommended by the store where we purchased the flooring. The bamboo was acclimated in our home for around 8 weeks prior to installation. Now the wood floor in one section under newly (3 month old island) is cupping however there is no water source or moisture in that area?? We have check all appliances and sink for leaks and have found nothing. What could this be from?

    • Jason Spangler says:


      Thanks for the question. It could be from multiple areas normally, but in this case, it seems to revolve around the new island and may have something to do with the weight of the island and/or the island blocking any potential breathability of the floor. I am just guessing. Your best bet is to either have the manufacturer come out and look at it or contact NWFA-National Wood Flooring Association at nwfa.org and find a certified inspector to come out and look at it.



  97. Ryan says:

    Good Morning!

    We are preparing to install a wide plank solid wood 3/4″ thick by 6.25″ wide hickory wood floor. Our house is 140 years old and the subfloor is not level in certain areas. We have done alot of work and leveled it to an extent, but it is still outside the thresholds of the 1/8 to 3/16 inch specified by the NHFA guidelines. The floor is fairly level east to west, but north to south it currently is not level but has a slope.

    What the are implications of installing wood flooring on a sub floor that is not perfectly flat? Will this cause buckling, crowning, cracking of boards or any other visual issues (other than the final floor product possibly not looking flat) with the hardwood floor itself?

    Thank you!


    • Jason Spangler says:


      Thanks for the post. You continue to say level. A floor not being level is ok. The question is, is the floor flat? Not being flat can cause problems with plank adherence to the floor, hollow spots, T/G not fitting correctly, etc. I would consult with NWFA, the National Wood Flooring Association, for any additional symptomatic problems that may exist.



  98. Brian says:

    I recently bought an used house (20 years old) and after removing the carpet in the living room, I found along one particular seam of the subfloor (I think it’s plywood) the edges are cupping. It runs from wall to wall but is more prominent on one side. There is a larger than usual gap along this seam and although there are screws and nails running down the seam on both sides, it didn’t prevent that seam from rising up like a lump. It’s almost a quarter inch higher at the peak than the ground level. I’m wondering what caused this and if I need to look out for something in the future. How do I fix it? I want to put laminate on this floor and I was thinking to just sand it down to make it level.

    • Jason Spangler says:


      Thanks for the question. It sounds like moisture may have caused this issue. The questions are this:

      1) Is this moisture differential coming from below or did it happen from the top?
      2) Is/was it an isolated instance or is it still an ongoing problem

      Sanding may help the symptom, but if the problem isn’t fixed then the symptom will come back with a vengeance.



  99. C clark says:

    Our house was built last year. We have a cement floor, wall crawl space . On the main floor we immediately noticed low spots in several areas, floor felt soft or hollow almost sinking – not solid underneath (sorry don’t know how to explain better) , builder said that high spots were actually the problem so added extra support underneath in crawl space, I don’t feel an improvement. Also have many loud popping and cracking noises that are worsening with time.
    Builder replaced one area in family room near fireplace explaining the glue had not adhered well. I believe we have engineered hardwood. Any input would be greatly appreciated!

    Thank you.

    • Jason Spangler says:


      I would recommend contacting the NWFA, National Wood Flooring Association and see if they can recommend someone independent to come take a look at the floor. This way, if there is something wrong with the floor, you can have very specific, unbiased information to provide to the contractor for resolution. I hope this helps.


  100. Jeremy Brown says:

    We have some cheap engineered flooring in our kitchen. We just noticed a couple days ago an area about 15-20sf that is mostly in front of the sink and dishwasher that is slightly cupping and splitting on many of the boards. Here’s the mysterious part – after pulling out the dishwasher and inspecting it (and the area in which is rests) and fully inspecting the sink and and cabinet underneath – everything there is perfectly dry. There is no evidence of a leak from the ceiling either. Nobody spilled anything (It’s just my wife and our two children and we surely would have seen and cleaned up a spill). And….the flooring up against the typical sources of a leak is actually unaffected anyway. In other words – it doesn’t seem to be traceable back to any one source. We know the flooring needs replaced, but not without first locating the source of the problem. BAFFLED.

    • Jason Spangler says:


      It could be water from dishes, as you are loading the dishwasher, getting on the floor. Little bits of water over time. If this is a floor over a crawlspace, there could be something different in that area like penetrations in the vapor retarder/no retarder, moisture accumulation in that area, ventilation, etc. Also, with the cupping and splitting, it could be a “dry cup” which means the ambient conditions are too dry. This can affect small areas of flooring. I would say that in the course of replacing the floor you enlist a knowledgeable installer to explain/help you identify the issue(s) and ways to avoid in the future.



  101. Bob Teachout says:

    My wife and I purchased a new condo with concrete floors, the builder never self leveled the floor and now there are several spots where you step you can feel the floor move. It’s engineered hand scraped hardwood. Also the builder got ceramic tile dust all over the floor and in the wood grain, when they tried to clean it up they just mopped it into all the grain and seams and it’s as hard as concrete. He wants to put stain over the entire floor, we let him try one room and in less than 3 months the white dust is coming back through. Are any of theses problems something you have experience with?

    Bob T

    • Jason Spangler says:


      Thanks for the question. I can’t say that we have had direct experience with this specific problem, but it seems to me the answers could be obtained by getting the right person (independent) to look at the job. Being that it is wood, I would contact NWFA at http://www.NWFA.org and look through their list of certified inspectors in your area. I hope this helps.


  102. Lisa Dodge says:

    We are refinishing the original wood floor in our house. There is a large area where a dog has repeatedly urinated. We dried the area with heat lamps and fans, finished the floor and 2 days after finishing the floor in that area was ruined with a bunch of moisture that came thru the wood. How can we fix this

  103. Rob says:

    I’m in the process of installing hardwood floors on my sub flooring. I just noticed that in the center of the room there is a lift of the wood flooring. The wood flooring looks to be completely intact to subfloor. It looks like there’s a wave in the flooring. I went under the house and noticed that in the lifted area – – there’s a support beam directly in that area. My house is 25 years old. Have I done something wrong while installing the hardwood floor, or is the sub floor uneven? The hardwood is in the house one week prior to the install.

    • Jason Spangler says:

      Rob, it’s hard to say for sure based on the information, but I would be leaning towards the flatness of the subfloor. I hope this helps.

  104. Nancy LeBoeuf says:

    My 90 year old house is 3 ft off the ground. My wood floors in the living room are buckling in the middle of the room. We have had 2 weeks of rain non stop. What can you recommend? We have a dehumidifier in the room but nothing is working. Help

    • Jason Spangler says:


      Thanks for the question. Unfortunately, based on the information provided, it is hard to say if it is the conditions in the house or from under the house causing the problems. I would go onto the NWFA.org (National Wood Flooring Association) website and call their hotline. They may be able to walk you through some of the questions and either give you solutions or recommend resources to look at the problem closer.

  105. Cotton Mendenhall says:

    I have obvious water penetration in my living area with my hardwoods buckled on a slab foundation. I live in Dallas. Do you have a recommendation on who I can call to check it out in Dallas?

    • Jason Spangler says:


      Thanks for the question. If you are looking for someone to measure the moisture levels in your concrete, here is one suggestion:

      Terracon Consultants, Inc.
      Engineering Consultant
      Address: 8901 John W. Carpenter Fwy #100, Dallas, TX 75247
      Phone: (214) 630-1010

      I hope this helps.


  106. Casey says:

    I have a condo with its original parquet floors from the late 80s/early 90s. The floor has started lifting up in places. I’m relatively certain it isn’t a moisture issue, as I had an inspection done upon move in 12 months ago, and no moisture detected. I’ve also felt around the area (it is near front door and laundry area) and can’t find moisture. I think it’s a combination of AGE and also FORCE/STRESS. What I mean by FORCE is- edge of floor comes up against the laundry area, and when the old washer is unbalanced it jolts around a lot. At times is pushes up against the parquet edge- I believe over time this is pushing the floor up. My question: is there a quick or temporary fix, other than new floors, for this? Screws or nails? Getting some new ashes under there? THANK YOU!!!

  107. Carlos Jimenez says:

    Mysterious Water stains in the middle of the living room. No plumbing near the vicinity in the crawl space beneath. No sense of humidity in the crawl space. New Roof was installed but when it rains the floor in the middle of the room gets wet.. When it does not rain all the wood seems to dry up except 1 piece which remains to always be wet. I really need some guidance on how this can be happening? House is under renovation and I’m looking into refinishing the floors as the last step of the reno.
    Carlos J.
    Miami, FL

    • Ron Smith says:

      Hi Carlos,

      I’d suggest trying to locate an ASHI-certified home inspector in your region to take a look at this and determine the source.

  108. Amy Wouda says:

    We recently renovated a 20 year old house the was built slab on grade. The house had parquet floors that we covered with a thick underlay and then laminate flooring. This work was done in May and in September the laminate started cupping. We were worried there was not enough space left along walls that the laminate butted into. However after removing the laminate flooring the problem actually lies in the old parquet floor. It has cupped terribly. It is the original flooring that was installed 20 years ago. I think now the laminate and parquet will both have to be ripped up, however what is the best type of flooring to lay down to not have this problem occur again?

  109. Teresa says:

    Bought our house about a month ago, guess the previous owners installed their own hardwood floors. In the front doorway and one other place in my house the flooring is rising up? I saw that one problem could be moisture getting into the wood. What can we do to fix it?

    • Jason Spangler says:

      This could be the result of inconsistent ambient conditions, improper acclimation, or many other moisture related problems. These types of problems can be fixed, but you really need a professional to diagnose the problem to come up with a remedy. I would attempt to identify a NWFA certified wood flooring inspector/installer to properly help you with this issue. The NWFA website is NWFA.org. I hope this helps.

  110. Connie Hargrave says:

    My new hardwood floors were installed about 2months apart (awaiting wood availability-carribean pine). They were left unfinished. Installer supposedly sanded first area and only slightly sanded second area. There are grout marks where bathroom was remodeled and shoe scuffs and now cracks developing between the boards and worst of all I have squeaky floors and flooring is butting against wall in many areas. Installer is arrogant and very difficult to talk to and becomes defensive and storms out of my house and raises his voice at me. He has been paid for all but about 6%. He refuses to use any other stain but Minwax.

  111. Fran Zwicky says:

    i just had new 3/4 quarter solid oak floors put in and am not happy with the installation. There are some gaps, chips in wood and one board is cracked. Some boards do not meet and have a rough edge. I am sick from this whole experience and don’t know what to do.

    • Jason Spangler says:

      Hi Fran,

      Talk with the installer to see if you can come up with a solution. If that doesn’t work, having an NWFA certified inspector come out and look at the floor can help.

  112. Roy Dreibelbis says:

    I had 3/4 inch (hard wood) flooring install a year ago over 3/4 inch sub-floor.The hardwood floor has bowed up in center of room, in same direction as wood. This goes from wall to wall of room. What is cause and how can it be repaired?

    • Jason Spangler says:

      Is the bow in each board width of the floor or is it just one big bow, where the entire section of floor is lifting off the subfloor?

  113. Kate Bristow says:

    I have cracks and separations between boards. Can I use a liquid cleaner?

    • Jason Spangler says:

      While you can use a liquid cleaner, I would recommend researching different types of products and determine if there is a specific one that may help address your issues.

  114. charles balasalle says:

    my first floor hallway floors,have signs of moisture on top of the hardwood floor boards>
    floor measurements are 3×18 most of the area are away from the front door door
    I do have central air. there is no cupping or buckling. I only have water./moisture satins.
    which i can feel with my hands. should i purchase a moisture meter ? would this help me find the cause or should i have a floor contractor look at my floor?

    • Jason Spangler says:


      I think in this instance, unless you were going to be using the meter on an ongoing basis, your money would be better spent either bringing in a wood flooring inspector or a wood flooring contractor to lend their professional opinion. NWFA.org can help you find qualified people to help.

  115. Zachary says:

    My floorboards are developing cracks/holes in the middle of the boards themselves; which seem to follow the pattern of the wood. Some say it is a natural process( the house is about 5 years old), but I was wondering if more polish, olive oil or other method could slow this process down?

  116. jason Spangler says:


    Great question. Unfortunately, I have a few questions prior to being able to give my opinion:

    1) Is this solid hardwood or engineered?
    2) Are we dealing with any transition pieces? If not, how long of a “run” of wood do we have without transition?
    3) Is the flooring installation direct glue down or nailed?


  117. Peter Barton says:

    Hi, I have a hardwood floor that seems squishy where the living room transitions into the hallway. I pulled the suspended ceiling and insulation from the basement cueing and didn’t see anything noticeably wrong. Any ideas what or where we should be looking for?

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