Rebuild a Bathroom Floor
LESLIE: Carl in Michigan is calling in with a saggy bathroom floor. What is going on there?
CARL: I bought a house about a year ago and I guess I didn’t pay much attention. It’s sagging towards the basement and what I believe happened, judging from after going under and looking from the basement up, is that the previous owners had allowed the tub to run over continuously over a period of years and it rotted the timbers out.
TOM: Oh, boy. Oh, boy. OK.
CARL: And I’m trying to figure out an inexpensive way to do it or do I have to go with an expensive way to do it?
TOM: Well, the first thing you need to determine is how far along the decay is. If the decay has only impacted the subfloor, then that’s one thing. If the decay has impacted the floor joist, then that’s another thing.
CARL: Floor joists.
TOM: Floor joists, too?
CARL: Two-by-eights, yep.
TOM: Alright. Well, so here’s what has to happen: you’re going to end up having to take out the sink; take out the toilet from the bathroom so you can have the ability to tear the floor up. You’re going to take up the whole subfloor down to the floor joists and then, where the floor joists are right now, what you’re going to try to do – and I can’t tell you if this is absolutely possible, because I can’t see it – but what you’re going to try to do is you’re going to try to sister new floor beams against the old ones. So you’re not going to take out the old ones; you’re going to put new ones against it. Think of it as a splint.
And you need to go end to end, as long as possible on those sister beams, and that’s going to reinforce what you have and then you can rebuild the floor from the bottom on up. Yeah, you may have to get creative, because there’s going to be plumbing and wiring and all that in the way. But you want to get as many new beams against the old beams as possible, so that you can carry the load.
CARL: OK. Since that basement is not finished and I’ve got – I can visually see the joists – is there any way that I could maybe get like a jack, you know what I mean? One of those jack deals and jack the bad – good board – the bad boards up and sister them in from the bottom?
TOM: Well, you want – the idea is to try to get them all in a line, if you possibly can. And you may need to temporarily lift them with a jack while you’re doing that. But what you want to do is secure the old boards; the bad boards to the good boards.
CARL: Right. And if I can get that floor back level that way and put the sister joists in there, I’m good to go, you think?
TOM: Yeah. Do you have a second bathroom in the house?
CARL: Nope, unfortunately not. Hidy ho.
TOM: Oh, man. So, you’d better plan this out carefully, my friend, because you’re going to have to get it all done in one weekend and in between, you’re going to have to go knock on the neighbor’s door or something.
CARL: OK. Yeah, OK. So that’s what it will take, huh?
CARL: The best way to do it would just be to pull that floor up out of there?
TOM: Yep. That’s the best way; it’s the easiest way to do it and essentially rebuild it.
TOM: Good luck with that project, Carl. Thanks so much for calling us at 888-MONEY-PIT.
Man, that’s tough when you’re doing a bathroom makeover and you’ve only got one bathroom in the house.
LESLIE: And it’s your only one.