Rant: A job in a 1920s bungalow in Portland made me rethink my whole underlayment game

I was putting down some engineered hardwood in this old house, and the homeowner wanted it to feel solid, no flex. I used my usual 6mm foam underlayment, thinking it would be fine. About halfway through the main room, I stepped on a spot and felt this tiny, almost silent squeak. It was barely there, but I knew it. The original plank subfloor had just enough unevenness that the foam was compressing and rebounding ever so slightly. I ended up pulling up a few boards and putting down a layer of 1/4 inch plywood over the subfloor first, then the underlayment on top. It added a day to the job, but that floor is dead quiet now. In my experience, that old rule about just checking for flatness isn't enough on these really old houses. You have to think about the long-term compression of the pad over decades of tiny gaps. Has anyone else run into this with pre-1950s construction and found a better fix?

3 comments

3 Comments

dylan41327d ago

Totally agree. That thin foam just can't handle the reality of an old plank floor. I've stopped using it on anything built before plywood was standard. Even with a good flattening pass, those planks move independently. The plywood layer is the only real fix. It ties everything together into one solid surface. Anything less is just a temporary quiet.

xena_rivera6327d ago

That line about "temporary quiet" hits hard. It's like putting a band-aid on a broken pipe. I see it all the time with quick fixes on old houses, people trying to avoid the real work. They'll spend money on three cheap solutions instead of just doing the one solid repair that lasts.

paige_martin9d ago

Yeah, that "temporary quiet" thing is the whole problem. It feels fine when you walk on it the first year, but that foam just gives up over time. Those old planks aren't just uneven, they breathe and shift with the seasons. The plywood isn't just for flatness, it creates a whole new, stable skin that the old floor never had. Skipping it is basically betting against physics and the house will win every time.