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Poll: What would you do?
Sell the laminate and forget the studio
Keep the laminate and find a knowledgeable installer

Laminate on concrete slab
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07-22-2012, 07:00 PM #1
Dancer Newbie *
Status: Offline Posts:2 Threads:1 Joined:Jul 2012
I'm a dancer and my house has a bonus room downstairs (i.e., finished basement) that I wanted to turn into a studio. I went to the local Lumber Liquidators and explained what I wanted to do. The best approach seemed to be laminate because I needed cushioning for dancing. (The kind i purchased has a sort of black foam attached to it.) It was also more economical than trying to build a floating floor.

I also purchased a separate moisture barrier. It's blue and foam like. I actually bought all this two years ago and some details I cannot quite remember. I still have the laminate but never installed it. Currently there is carpet and it is due to be replaced.

I would like to have the laminate installed now but have since learned of all the moisture problems with basements. Are my dreams to have a home studio gone, either because laminate is a terrible idea or because it would be cost prohibitive to ensure a successful installation with no mositure leakage? Are there other options I might not be considering? (Replacing the carpet is the last thing I want to do because of my allergies.)

An acquaintance who is a contractor said I should put s layer of tar down. That really blew my mind!

I don't want to spend money on installation if I'm going to end up with warped or moldy floors. I would really appreciate some guidance from experts. It seems relying on the store to give me all the right information was a colossal mistake.

Thank you!

07-22-2012, 07:41 PM #2
CC Solutions Concrete Moisture Evangelist *******
Status: Offline Posts:1,067 Threads:69 Joined:Dec 2009
First of all welcome!

And secondly, it CAN be done.

Have you noticed moisture on the floor before?

I don't do residential work, but some good guys here do and can advise you. In the commercial world of hospitals I work in we kind of overkill everything, but I know I could put your floor in with no moisture issues ever. At least you can relax knowing that!

If you haven't noticed a damp floor ever, you are in pretty good shape. You could lay a sheet of plastic over an open area of concrete and see if water forms under it. If it doesn't that's great! If it does, well you need to prepare more.

If your floor is a floating floor, I would think a good vapor retarder laid over the concrete before the laminate will work wonders. And it would be less smelly and messy than tar! Wink

You should reply with the brand and name of your flooring and any moisture issues you have ever seen. That will be a good place for our residential experts to start.

JD Grafton
Concrete Answers for Flooring Problems

07-23-2012, 11:15 AM #3
CCR Concrete Moisture Coach ***
Status: Offline Posts:236 Threads:14 Joined:Dec 2011
What about flatness? Very critical here for proper fitting and to avoid any deflection or movement of the installed laminate. Is there a drain with a slope? If so, some leveling will be needed prior to anything going down. Concrete does not need to be dead level, but it does need to be flat! Forget the tar. That's the most ridiculous recommendation I have heard.

JK Nixon
Concrete Restoration Services, LLC
Pittsburgh, PA

07-24-2012, 03:24 PM #4
eaadams Concrete Moisture Expert *****
Status: Offline Posts:600 Threads:88 Joined:Jul 2010
Sounds like they want to treat a basement like you would hot mop a shower.

Ernesto needs to weigh in, he does by far the most residential laminate on the board.

07-24-2012, 04:01 PM #5
CC Solutions Concrete Moisture Evangelist *******
Status: Offline Posts:1,067 Threads:69 Joined:Dec 2009
I was hoping Ernesto would see this.... I'll PM him.

JD Grafton
Concrete Answers for Flooring Problems

07-30-2012, 03:58 PM #6
Ernesto Concrete Moisture Expert *****
Status: Offline Posts:606 Threads:33 Joined:Sep 2009
Is it to late to chime in?

First, double layers of underlayment are usually a no-no with floating floors. Although I have used cork and attached cushion. Also Quick-step makes a rigid underlayment for people who want more insulation. The thing is it cannot be to soft or the locking mechanism may fail.

Below grade it is all about protection against moisture. Anything with a drain is a no no but have done that. If your in an area prone to high water table I'd say forget it unless your basement has been sealed up by a professional. Then temp and relative humidity always plays a part with laminate and wood flooring. The basement needs to have a controlled environment, rh and temp within the zone required by manyfacturers, typically much the same as hardwood floors. Even vinyl planks have moisture, temp and rh requirements.

I'd do the plastic sheet test if you can get the environment controlled, and for a week to stabilize it first. Lots of moisture undere the mat will tell you that it would not be a healthy environment for either you or the floor unless you spend lots of money on an epoxy vapor system. Go with a heavy 8 mil plastic vapor retarder plus 2&1 cushion/vapor retarder and run the plastic up the walls. Finish with a vinyl or rubber vented cove base made for sports floors.

For the record, layered roofing mastic and plastic was a very viable vapor retarding system and approved by NOFMA and the NWFA for hardwood floors over concrete with a sleepr system or fastened down ply over concrete.

Stephen Perrera dba
Top Floor Installation Co.

08-15-2012, 09:36 PM #7
Dancer Newbie *
Status: Offline Posts:2 Threads:1 Joined:Jul 2012
Thanks for all the input! I'm sorry I didn't reply sooner but I wasn't alerted to the postings through email as I had expected to be.

The manufacturer of the laminate is Dream Home.

I will do a plastic sheet test in the unfinished basement where there is no carpet and see what happens. So far it looks like the moisture is coming through the cedar block-like walls, not the floor. And those walls are not in the finished part of the basement where I want to place the laminate.

But everyone gave me a lot to think about.

The finished part of the basement is hooked into central HVAC system and is generally cool. Does that make a difference?

Thanks again!

08-16-2012, 10:56 AM #8
CC Solutions Concrete Moisture Evangelist *******
Status: Offline Posts:1,067 Threads:69 Joined:Dec 2009
HVAC will make a difference. Think of your concrete as a big sponge. If the air is humid the concrete may absorb moisture, if the air is very dry the concrete can emit moisture.

Another consideration is the concrete on grade is typically cooler than the airspace around it because it is in contact with the cool ground. A slab at 65 degrees may collect condensation if the temperature and humidity in the air around it gets to about 75 degrees and 70% RH.

The plastic sheet test will show you if the slab is actively emitting a large amount of moisture during the time you have the plastic in place. Only a relative humidity test will show you if there is a large amount of moisture in the concrete just waiting to cause you problems. It's for this very reason that most flooring manufacturers are rejecting the antiquated calcium chloride test for moisture emission and are embracing the relative humidity test. Wink

JD Grafton
Concrete Answers for Flooring Problems

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