What is the absolute BEST way to attach 5/8 ply over concrete in order to install a thin solid wood on top. Not better for contractors better for the floor!

I had one guy want to seal the concrete with a sealer than glue AND fasten the 5/8 ply.

Then I have another want to use the 6 mm plastic to seal and just fasteners to attach the ply.

I like guy one.

yes guy one has the idea, sealer to prevent moisture from comming through, glue and tapcons to hold the plywood down.

We (contractors) Dont add things on to make more money, we add them on to make your floor better, and last longer. We dont want to do the extra work, or spen extra money on materials if its not needed. What is nofmas stand on this?

Ok then you two disagree despite the misprint "guy one" in response two.

As one voted for using glue and fasteners another just fasteners. I guess I expected that.

actually (floor guy) and I agree. Guy number one wanted to seal, glue and fasten the subfloor down.


My house Id go that route. You always get what you pay for.

thanks for clarifying. I never mind paying more for a better job. It is quite funny but the plastic/fastener guy is actually charging more than the MVP/fastener/glue guy who is also including felt!

I know who is ripping me off

PS nice to see some confidence in sealers.

NP, I have seen it done all kinds of ways, Ive seen glue and screws (no plastic or sealer) Ive even seen nothing just concrete nails (horrible)
Make sure they are going to use "Tapcons" Or some other similar cement "screw" like fastners. The cement "nails" Dont hold for very long. Think of how nails dont hold wood as good as screws...

I dont know youre area, but tapcon/glue/sealer plywood down, would be an estimate of 50-75 per sheet (35 sqft) Also make sure its CDX plywood.

Prior to the concrete sealers like MVP and others (there are many now), I would level and prep the slab, lay an inexpensive vinyl floor, then full spread glue down 3/4" CDX plywood with Franklin's "Advantage" adhesive plus hand nail 1&1/2" fluted masonry nails into the slab with a 2 lb. sledge hammer. I kerfed the backside of those 4 x 4 plywood panels as well. With this method, I achieved a rock solid, moisture resistant substrate to nail 3/4" solid flooring over. In addition, I installed the typical 15 lb. asphalt felt over the plywood. It was expensive and time consuming. NOFMA does have recommended procedures for attaching plywood to concrete. Using "tapcons" isn't one of them, although that should work.

Gary Tapcons arent the supported way? I had always thought they were. Honestly I never researched it, Just seemed that everywhere I had worked before opening my own company had used them. 8 out of the 10 companies. The other 2 used those fluted nails (1 inch) I assumed that was not the preffered method it just seemed like too easy of a solution, and the whole nail vs. screw therory.

But atlast in the end I assumed the answer all these years, we all know what that means

The only written recommendation by NOFMA for mechanically attaching plywood to concrete (not gluing or floating) is to use powder activated fasteners or hand nail. Read page # 4:
http://www.nofma.org/Portals/0/Publicat ... Floors.pdf