How to Replace Bathroom Floor Underlayment

  • Transcript

    LESLIE: Now we’re going to take a call from Oregon with Debra who’s dealing with a flooring issue in the bath. How can we help?

    DEBRA: My bathroom had a problem. There was a leak and the particleboard flooring overlayment rotted away, so I’m attempting to do it myself. What I’d like to know is what type of overlayment should I be using and how thick.

    TOM: I think you mean underlayment. (chuckles)

    DEBRA: OK, underlayment. Yeah, there’s two …

    TOM: Hey, some people call it over; some people call it under. (Debra chuckles) It’s a floor, one way or the other.

    DEBRA: Yes, I’m …

    TOM: Well, is the leak under the toilet? Is that what happened?

    DEBRA: Yes.

    TOM: OK.

    DEBRA: And the wood rotted away and …

    TOM: Alright, so here’s what you have to do. First of all, obviously you have to remove the toilet.

    DEBRA: Right.

    TOM: Secondly, you’re going to – now what kind of a sink do you have in there? Is there a vanity that’s going to be near the toilet?

    DEBRA: Yes.

    TOM: Well, the best thing to do, believe it or not, will be to remove that as well because what has to happen, you have to cut out that rotted floor. And if you’re going to – is this only one layer of subfloor here? Is it an older house and you have multiple layers? Because if you’re going to cut through the floor joist, you have to cut something wide enough where it goes beam to beam. Do you follow me on that?

    DEBRA: Yes, I do. Matter of fact, someone did repair that portion of it.

    TOM: OK.

    DEBRA: So that part has been done but now I’m going to do that other layer that’s on top of it.

    TOM: (overlapping voices) OK. Do you have anything else that you have to match to it? Is it halfway there in some other part of the bathroom or has the entire floor been replaced?

    DEBRA: Yes, just the part around the toilet, oh, there’s been like a couple of feet – two feet, two-and-a-half feet – that …

    TOM: OK, well what you have to do here is you have to see what was there before because you have to match the thickness. There are different types of underlayment material. Sometimes there’s plywood – like luan plywood; sometimes there’s waferboard.


    TOM: OSB. So you need to figure out what was there before and match the height. And then what kind of finished floor are you going to put in?

    DEBRA: I’m going to put a linoleum down.

    TOM: OK, that’s one option. Another one that might be easier is laminate floor. Because laminate floor is going to be more forgiving of the unevenness of that repair job. And laminate floor can be installed pretty easily by yourself because all the pieces are locked together; they all snap together today.

    LESLIE: Yeah, if you go linoleum, because it’s a sheet product it’s going to sort of rest into areas where the floor, the underlayment is uneven and you’re going to notice a lot of those dips and dives.

    DEBRA: Yeah, I’m going to replace the entire thing because it was particleboard and the water spread out quite a bit.

    TOM: I think that you’ll find that the laminate floor is the best way to go because it’s a very sturdy floor; plus it comes in just hundreds of different patterns. You can have one that has a pattern similar to a vinyl floor or you can go something that may represent a wood floor. And it’ll be permanent, it’ll be moisture-proof and it’ll look great.

    DEBRA: OK. About the fixture, the toilet fixture, how do I get underneath that lip that’s there?

    TOM: (overlapping voices) Underneath the lip that’s there?

    DEBRA: (overlapping voices) The height.

    TOM: Well, once you put the new subfloor in, then you’re going to make sure you raise the pipe so that it’s flush with the finished floor. And that’s a plumbing project. And you’ll use a new wax seal between the drain and the toilet.

    DEBRA: OK. And it has to be flush?

    TOM: Yes. Well, fairly close. If it’s not flush, you may have leaking issues.

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