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Engineered Hardwood over concrete slab floor

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Nov 25, 2013, 11:05 PM
jabdal
Engineered Hardwood over concrete slab floor
I have purchased oak hardwood engineered floors that I plan to install over a concrete slab foundation. I am considering laying down a plywood subfloor so that I can nail down the wood floor. I know that I need to put a moisture barrier between the slab and plywood which rules out gluing down the plywood. Is there another quick way of attaching the plywood to the slab?
Nov 26, 2013, 09:19 AM
Jaybee
I'll say this first: You will be far better off if you return your nail-down material and install a floating engineered floor. Much less expensive, MUCH easier install and easier replacement in the event of moisture damage or flooding.

There is no easy way to attach a plywood subfloor to concrete. Even with 3/4" thick material, you will need fasteners set on 8" centers - that's 91 Tap Cons or masonry nails per sheet. Even at that, the impact from installing the hardwood flooring on top is bound to loosen up some of the nails or screws.

You can make a floating subfloor out of two layers of plywood with overlapping seams, but this will basically give yo a floating floor system - much better just to start out with a floating floor.

Your choice, but I would return the nail-down and go with another product.


Jaybee
Nov 26, 2013, 04:08 PM
nona
my engineered flooring was glued onto my concrete slab, per the manufacturers ( Anderson ) instructions, about 7 years ago. There hasn't been any problems yet and I don't foresee any in the future
You might be interested in checking out the Anderson flooring web site

This message has been edited. Last edited by: nona,
Nov 26, 2013, 09:49 PM
jabdal
Thanks for the responses. I may have explained the type of flooring I purchased incorrectly. It is Engineered Harwood that can be installed by nailing, glue or floating. My thought was that if I nailed them down over plywood, I would get more of the traditional wood floor feeling.

This message has been edited. Last edited by: jabdal,
Nov 26, 2013, 10:45 PM
Jaybee
There is definitely a different feel to a floating floor - as they are installed on top of a mild pad there is always just a little 'give' as you walk across it. Not bad, just obviously not a nail-down or glue-down floor. But, a much easier install than trying to nail it down.

My only comments about glue down is that they don't always work on concrete. Getting a perfectly level concrete slab without any high or low spots is difficult. A glue-down floor that runs over a slight low spot can release over time and 'pop' as you walk across it. It is enough of a problem that most of the hardwood floor companies in our area will not do a glue-down on a slab. Even if there are no low spots, if a slab has any hairline cracks that can move just a little with changes in the water table it will directly affect a glue-down floor.


Jaybee
Nov 26, 2013, 11:06 PM
jabdal
I live in North Dallas and there is one thing you can count on and that is the foundation will shift. I installed a marble floor in the entry way over concrete backer board and it cracked with a shift in the foundation. I had ruled out gluing it down from the beginning. One question with the floating floor if the wood is not click and lock what is there a risk of not gluing the planks together? My thought is that if I have to repair it would be easier but I don't know how much the planks could shift and leave gaps.
Nov 27, 2013, 09:02 AM
Jaybee
If it's not a click type floor than you have to glue the individual planks together to make it into a floating floor. No options there - a typical T&G floor will not stay together.

Glue together is usually a professional type install - there are a few simple tools like ratchet straps needed - but it takes a technique and some practice to get a nice, tight fit.


Jaybee