Hardwood Floor Moisture Problems: Learn the Warning Signs

Caution: Wet Floor

Wood’s moisture content (MC), the amount of moisture in wood, must be managed to achieve optimum flooring strength and durability. When relative humidity (RH) rises, wood absorbs moisture from the air. When RH falls, wood emits moisture back into the air. This natural process gives wood its strength and beauty, but excessive MC can cause many possible problems with your wood floors.

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 ProblemCracks 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 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.

Cupping: 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. Cupping most often appears after the floor has been installed and may or may not be an installation issue.

Crowning: 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.

Buckling: This is the most extreme reaction to moisture in a hardwood floor. This 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. 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. Once the floor has dried to a more stable moisture level, repairs can usually be made.

Invisible Moisture Problems

Some moisture dynamics can occur beneath a flooring substrate with equally devastating possible consequences for wood flooring applications.

Wood SubfloorWood Subfloors: Determining MC is an essential part of 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 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.

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.

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, ground water intrusion through a perforated vapor barrier, condensation, and even moisture from a concrete subfloor that had not completely dried can introduce moisture to your flooring equation. Also from the outdoors, it might be the terrain of the home’s lot with rain and runoff not moving away from the foundation that 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.

Take a look at our moisture meters here.

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Jason Spangler

Jason has 20+ years' experience in sales and sales management in a spectrum of industries and has successfully launched a variety of products to the market, including the original Rapid RH® concrete moisture tests. He currently works with Wagner Meters as our Rapid RH® product sales manager.


  1. 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?

  2. 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?


  3. 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?

  4. 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.

  5. 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.

  6. 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?

  7. 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.

  8. 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.

  9. 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.

  10. 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?

  11. 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.

  12. 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!!!

  13. 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.


  14. 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.

  15. 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.

  16. 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

  17. 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.


  18. 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.



  19. 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.


  20. 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.



  21. 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.



  22. 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.



  23. 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

  24. 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

  25. 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.

  26. 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.

  27. 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

  28. 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.

  29. 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.



  30. 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.


  31. 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,

  32. 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.



  33. 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.


  34. 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.



  35. 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.



  36. 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.



  37. 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.


  38. 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,


  39. 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.

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