Hey everyone! My wife and I just bought a house from 1936 that has been renovated to add some extra bedrooms in the attic. We recently removed the old carpet, and underneath, we found a plywood subfloor that feels a bit bouncy and has some give in certain areas. We haven't checked how thick the subfloor is yet since we haven't pulled up the other layer. A contractor suggested that we strengthen the existing plywood by laying down 3/4" plywood on top before installing new flooring. Does this sound like a good plan? Is it reasonable?
3 Answers
Definitely use a sealing primer like Kilz on the existing subfloor, especially since the carpet was in bad shape. This will help with any lingering odors. Don't forget to address any squeaking too!
If you're up for it, I recommend pulling up the old plywood before adding a new 3/4" layer. If the floor feels bouncy, there might be issues with the joists underneath. It's best to inspect them now rather than later. If you just put a new layer down and the bounce persists, you'll end up having to remove two layers later on to fix the problem.
We were thinking about pulling up some sections to take a look at the joists. Good idea! We want to make sure we do it right the first time.
I did exactly this in my mid-1930s home, except my subfloor was shiplap. If you have air ducts, pull up the registers to check the layers, or drill a small hole to measure the thickness. To prevent squeaks, secure the existing plywood to the joists with #8 construction screws. I used 2" screws to avoid hitting any hidden wires or pipes. Make sure to hammer down any nails above the surface and position screws every 6" on the edges and 12" in the middle. When adding the new plywood, glue and screw it to the joists, not just the existing subfloor. I used 3/4" CCX T&G plywood and followed the standard screw pattern for best results.
For squeaking, do you mean I should screw down the original subfloor more securely or just add new nails?