Been cutting my own underlayment for years, but a job in Phoenix showed me I was wrong

I always trimmed my foam underlayment about a quarter inch from the wall, thinking it needed room. A homeowner there pointed out a draft and a slight echo in their new LVP floor. I checked and the gap was letting sound travel and cold air seep in. Now I butt it tight to the wall and the difference is huge. Do you guys cut it tight or leave a gap?

2 comments

2 Comments

reese5502d ago

That "fine desert dust" line got me... I was the guy leaving the half inch gap and basically building a tiny dirt highway under every floor. Felt pretty smart until I had to pull a baseboard and found enough sand to fill a kid's bucket. Cutting it tight and sealing it just makes too much sense, you stop the sound and the crud. I guess we all have to learn the hard way sometimes.

sean_ramirez2d ago

My old boss in Tucson swore by a half inch gap for expansion, but we kept finding dust bunnies and debris in that channel after a year. I switched to cutting it tight and using a bead of acoustical sealant along the bottom plate. It kills the hollow sound and stops that fine desert dust from getting under the floor.