Floor Under Carpet Squeaks: How Can I Stop It?
LESLIE: Patty, you’ve got The Money Pit. How can we help you today?
PATTY: Yeah, I’ve got a problem with squeaky floorboards. I’ve heard suggestions of going under the house with some shims to try to solve the problem that way. I didn’t know if there might be a better solution.
TOM: Sure. There’s lots of ways to address this.
So, Patty, what kind of floor are we talking about here? Are we talking about a hardwood floor? Or is this like the flooring under carpet?
PATTY: Flooring under the carpet.
TOM: OK. Alright. So, the flooring under the carpet. So the tough thing here is that the carpet is in between you and the solution. The reason that’s happening – and one more question. How old is your house?
PATTY: Probably about 27 years old.
TOM: So, you probably have plywood floors. They most likely were put in with a type of nail known as a cooler nail. And when the carpenters drive that nail through the plywood, into the floor joists, theoretically, the rosin is supposed to melt. And then when the nail stops, it sort of freezes in place.
But in actuality, that doesn’t happen all the time. And so, when you step on these boards, they loosen up. And because the nails have rosin on them – you think of rosin like on the bow of an instrument? It has a lot of friction, right? So it really increases the squeak factor as that nail moves in and out of the space between the plywood and the floor joist below. And you can also get squeaks when the boards rub together.
So how do we make this go away? How do we make it quiet? There’s two approaches. First of all, if you want to try to silence a squeak and not remove your carpet, what you can do is identify the place where the floor is loose and it’s on top of a floor joist. Now, you can do that with a stud finder. Stanley Tools has lots of different stud finders that are anywhere from a few dollars to $25 or $30. And it can tell you exactly, by sort of looking through that carpet, when you’re over a floor joist. Then what you do is you drive a Number 10 or Number 12 galvanized finish nail through the carpet, through the subfloor, into the floor joist.
Now, when you’ve finished driving it, it’ll look sort of like the carpet is dimpled in. But you can pull that carpet nap and pop it sort of right through the nailhead and it will sort of disappear below the carpet that way. If you do that in a couple of places, you’ll quiet down that spot because you’ll be basically securing down that loose subfloor to the floor joist below.
But the best way to do this is to pull up the carpet. And then, what you would do is you would get case-hardened screws that are put in place with a drill with a screwdriver tip on it and basically shoot these screws in, about 4 or 5 of them across every 4-foot depth of the plywood into the floor joist below. This will lock that floor down and it will never, ever pull up again and you’ll get rid of 90 percent of the squeaks. There’s probably going to be one or two somewhere that you can’t get rid of but for the most part, you’ll get rid of them completely.
The idea of going under the floor and shimming has to do with the idea of going under and looking for little gaps, perhaps, between the plywood and the floor joist. And it can work in certain circumstances but it’s certainly not a comprehensive approach. If you did do that, what I would do is I would insert shims with a construction adhesive on both sides of it so it’s kind of glued in place. But really, what you really want to do here is secure that plywood floor down to the floor joist better, because it’s loosened up over the years. And that’ll make your squeaks disappear. Does that make sense?
PATTY: Yeah. You said galvanized nails and what length or what …?
TOM: Yeah. Number 10 or 12 galvanized finish nails. And if you look up on our website how to silence a squeaky floor, you’ll get the instructions there, as well.
PATTY: Oh, OK. Alright. Well, thank you so much. I really appreciate your help.