Condensation on Laminate Floor
LESLIE: Michelle in Minnesota is on the line with a bathroom-floor thing is all I can call it. What is going on? You’re getting moisture coming up through the floor?
MICHELLE: Yes. It’s a laminate floor. This is my third summer in this house and it’s the first time that I’ve had this issue. And it was – started around the warm and humid days. At first, I thought maybe that it was my toilet leaking, because I had a new toilet put in last summer. But the plumber did come out and pull the toilet and it didn’t look like it was leaking or that the seal was broken on it. So we’re thinking that it’s condensation from the concrete slab coming up between the slats of the laminate flooring.
TOM: So the laminate flooring is on top of a concrete slab?
MICHELLE: Correct, yep.
TOM: What’s this looking – what’s this doing to the floor? Is it causing it to deform in any way? Or is it just showing up as a stain?
MICHELLE: It is not buckling or anything along the edges. He thinks that maybe it’s a rubber flooring – more of a rubber based flooring – rather than a wood. And so it has not curled edges or anything like that. It just heats up as moisture – and it comes – like beads up right along the edges of the laminate.
TOM: Do you have air conditioning in this bathroom?
MICHELLE: I do not. Nope.
TOM: Yeah, I was thinking cooler, moist air against a warmer floor could cause additional condensation.
So look, if you want to reduce the moisture that’s coming up through the bathroom, there’s a couple of things I can suggest. First of all, you want to take a look at the grading and the drainage conditions outside that bathroom. Because the slab, if it’s getting very wet, is extremely hydroscopic. So all the moisture in the earth will be drawn into the slab and that’s going to wick up and show up in your bathroom, apparently.
So, take a look at your gutters and downspouts. Make sure gutters are clean and free flowing and the spouts are extending 4 to 6 feet from the house. Get all that roof water away and then take a look at the angle of the soil and make sure that that’s sloping away.
Now, do you have a fan in this bathroom?
TOM: That is helpful. You might want to think about replacing the fan with one that has a built-in humidistat, because that’s convenient in a couple of fronts. First of all, when you take a shower and you leave the bathroom and turn the switch off, it’ll actually stay on until all the moisture’s properly vented out of there. And if it does get humid on its own, then the humidistat will kick the fan on and also dry it out. They’re not terribly expensive; I know Broan makes a good one. There are a number of manufacturers you can find this from.
And keep an eye on the floor. Some laminate floors, you know, stand up very well to moisture. I’ve seen laminate floors that can be submerged and they don’t seem to be affected by it. But others will buckle just like hardwood would. So just keep an eye on it. And if it ends up that it does have to be replaced, I would paint that cement slab underneath with a couple of coats of epoxy paint to kind of seal in and stop the moisture from evaporating through and into the room.
MICHELLE: Mm-hmm. OK.
TOM: But only if you get that far. I wouldn’t tell you to tear up the floor now. But if you have to replace it, just make sure you seal the slab at the same time.
MICHELLE: Mm-hmm. Yeah, OK. Thank you. That’s good, thanks.