Installing a wood floor over concrete.
I am planning to use one of my garage bays as a home workshop. I would like to install EPS foam board and two layers of plywood over the concrete floor. I was planning on using 2 layers of plywood, the first layer would be 3/4″ T&G, fastended using 2-1/2 concrete screws. Second layer of plywood is 1/2″ plywood laid at right angle to the first course. I was wondering if this type of floor will be rigid enough to support a heavy machinery like a table saw without the floor permanently sagging. The other alternative would be to install sleepers on 2′ centers and lay EPS between the sleepers and only 1 layer of plywood.
I read in Fine Homebuilding #169, on using this type of floor system in a finished basement, and I was wondering if it would work in a shop.
I like the idea of a wood floor, less stressful to stand on than concrete, and would be warmer in the winter.
Thanks for your help.
Rocky
Replies
Sounds like it would work well.
I might start with the 1/2" ply first. You might have slight inperfections on the floor. More flex than 3/4" Might look at slight floor leveling or use 1/2" ply for the second course too. All depends on the concrete.
The foam board will eventually crush down and allow your floor to start sagging. It would be better to lay sleepers with the EPS between them and the ply screwed down to them.
Use Tapcons and PL Premium to fix the sleepers to the concrete slab. Notch the sleepers on the bottom side to allow for drainage of any water that gets in there towards the floor drain. (And make sure the floor drain has an anti-backflow valve on it.)
Contrary to popular misconception, you do not have to use PT lumber for the sleepers. Cured concrete has no ill effects on standard framing lumber in contact with it.
Dinosaur
How now, Mighty Sauron, that thou art not brought
low by this? For thine evil pales before that which
foolish men call Justice....
My shop floor has 1X4 sleepers running east west over the concrete, 16 inches on center. Then 3/4 plwood over the sleepers and finally 2 1/4" maple flooring running north and south. It's almost as good as my kitchen floor.