Hello again. I used asphalt shingles to level out a section of subfloor I had to replace (plywood isn't exactly 3/4" ). The thickness was perfect, but now when I step on the shingles there is a crunching sound from all the little pebble-like pieces that came off the shingles. I put the shingles in upside down for some reason, so the textured side is facing the plywood. I guess that was kind of stupid.

Should I turn all the shingles around or do you think that crunching sound will stop after all the little pieces settle in?? Anyone have experience with this? Thanks.

I staple mine down very well. This helps a lot. Vacuum up the loose grit. After that, place some flooring over it( don't install, just loose lay ) and walk on the wood. Does it "crackle and crunch"? If not, you're good to go.