# Fastening Subfloor Plywood To Concrete Slab



## JazMan (Feb 17, 2007)

Hi Tia,

That type of installation will not work most of the time and I know of no manufacturer that approve of it. 

You should check with the manufacturer if it's even recommended to install that type of hardwood over a concrete subfloor. Maybe you should have chosen engineered hardwood which usually can be glued directly to the concrete as long as the slab is not below grade level. It sound like yours is 3/4" thick solid wood?

Jaz


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## Hages (Feb 8, 2007)

JazMan said:


> Hi Tia,
> 
> That type of installation will not work most of the time and I know of no manufacturer that approve of it.
> 
> ...


I've spoken to a couple hardwood floor installers and that is what they would do. I am in California so climate conditions are quite moderate. Above grade and no frost conditions out here.

3/4" Plywood subflooring then 3/4" hardwood flooring

Thanks for your input and btw, "TIA" = Thanks In Advance


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## JazMan (Feb 17, 2007)

People do all kinds of things. I will admit that under certain conditions it has a much better chance of working out where most people would be happy. There are many variables. 

Why not check with the manufacturer to see what they have to say? What brand is it anyway? 

Thanks for the TIA clarification. Actually I kinda knew that but I'm used to people giving their first name at these forums (not this one) and thought Tia was a nice name.:yes: 

Jaz


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## Hages (Feb 8, 2007)

Jaz,

I'll ask the supplier. Likely it is a generic red oak unfinished hardwood of no particular manufacturer.

But I am hoping someone can answer about the nailing of the plywood to the concrete......:whistling2: 

Rod


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## Zero Punch (Nov 15, 2005)

Try 1/8in masonry bit and a hammer drill 2in fluted masonry nails and heavy duty construction adhesive, make sure your concrete is clean and dust free.


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## Hages (Feb 8, 2007)

Zero Punch said:


> Try 1/8in masonry bit and a hammer drill 2in fluted masonry nails and heavy duty construction adhesive, make sure your concrete is clean and dust free.


Okay, thanks! That is a bit of work compared to those powder-actuated hammer nailers.

I asked at one of those big box orange place for advice and he suggested the 2x4 furring strips. But I said I am assuming the standard 1.5 rough flooring and he is proposing 3in to account for all that subfloor work? Again this is above grade and a concrete pad foundation in a moderate no frost area.

I am thinking 12 nails per 4x8 subfloor. 

Looked at engineered wood flooring and it looks like artificial wood!! No thanks, plus it is also 3/4" thick and no way to get around the 3/4" plywood subfloor.

Do you folks think I can get away with this without the furring strips? Is it for air circulation for the wood? I really doubt I will have moisture issues plus I will have a vapor barrier between the concrete and wood.

TIA


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## Robert J (Jan 15, 2009)

Hages - What did you end up doing?


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## Robert J (Jan 15, 2009)

Hages - Please email info on what you did. Thanks, [email protected]


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## Hages (Feb 8, 2007)

*End Story...*

I ended up having a flooring contractor install engineered brazilian cherry with all the necessary vapor barrier membrane and foam. I was really concerned about potential gaps between the new flooring and the concrete, but it turned out fine!


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