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hello,
I’m planning to install a subfloor floor directly on the cement floor in the basement. Due to a low cieling, I will forgo 2x4s + subfloor and instead use half-inch x 3.5 + subfloor. What method should I use to attach these long half-inch pieces to the cement floor? Adhesive or Power nail them? Should I use regular pine? (is the proper word for these pieces of wood “strapping?”).
I’ve tested for moisture and fortunately there is none.
Regards
David
Replies
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David,
Many times I have attached 1/2" ply to concrete as a nailing base for hardwood flooring and I used parquet adhesive, spread with a 1/8" notched trowel and drilled and set tapcons to hold the sheet until the glue had set.
You may find that it is easier to use ply sheets than using long strips of wood.
Any irregularities in the concrete can be filled with self-levelling compound.
*Ian,Do think pl400 would work as well? Applied in lazy loops.
*David, we installed standard 2 1/2 x 3/4 inch red oakat grade over a cement (former garage) floor.We sealed the concrete first with Asphault compound,10 mil. poly over that, then 3/4 inch Douglas Fir"TPS" plywood power-fastened with 2 inch nails to the concrete.It rained 5 inches in 24 hours, 3 months later... no water problems. The yard floated, the kids toys in the yard floated, but the floor remained dry.-gwc
*In my experience, PL400 between wood and concrete is almost like welding. You Hilti (powershot) the high spots. The PL will bridge at least 3/8". You may find that 1/2" sleepers are a little thin to get much purchase into with a screw when laying the subfloor ply. If you have to, use a pneumatic stapler and more glue between sleepers and subfloor. Good luckAlan
*I don't think it would be as easy, Jim, for a couple of reasons.The bead of adhesive would be much thicker and there'd be more chance of voids left under the ply.The construction adhesive skins over a lot quicker than parquet adhesive (which is basically PVA with filler added to make it gap-filling)The way I did it was to pour the adhesive on the ply sheet and trowel it out then flip the sheet over into position and drill straight through it into the concrete. I never had a failure with the system -- or a squeek!If I wanted an added moisture barrier I used trowelable asphalt adhesive, trowelled on in the same way but with a 1/4" notch.
*Thanks Ian........seems like we got two spots for one thread.