Best Way to Add Heated Bathroom Floor

LESLIE: Tim in Illinois is on the line and looking to add heated bathroom floor. How can we help you with your project?

TIM: Redoing a bathroom in a 100-year-old house. And we’re looking at putting floor tile down, possibly with heat under the tile. And I was wondering what – the best way to do it. By putting the tile on, do you need to go right to the subfloor or do you have to have some kind of concrete board underneath the tile with doing heat under the floor?

TOM: Well, sometimes the heat is actually put underneath the subfloor itself, so that’s another way to add heated bathroom floor from the back side of it. Depends on your access issues. But there’s a special type of subfloor that’s designed for radiant heat or sub-slab heat where, especially if it’s PEX-based, the piping runs through a channel in the subfloor itself. So there’s no chance it could get crushed or anything like that. It’s sort of a channeled-out piece of underlayment.

And then once that’s done, you can put your tile adhesive right on top of that and glue the tile to that underlayment.

TIM: OK. This is in an upstairs bathroom, so we won’t have access to the bottom side.

TOM: What kind of a heating system are you thinking about putting in? Is it going to be electric?

TIM: It’ll be electric. We have geothermal in the house itself, so we’ve got forced-air heat. So it would have to be – I think they have some kind of electric under-mat or something like that. And also, I was wondering, is it best to just do the areas where – the main traffic areas? You don’t need to do the whole floor. Is that correct?

TOM: No, you don’t have to. It certainly is nice. You don’t have to go around the toilet to add heated bathroom floor, for example. So, yeah, if you went in front of the sink, in front of the toilet and wherever you step out in the shower, then that should be fine.

And yes, some of those electric heating systems are really nice. They don’t use as much electricity as they used to. You can set them up on timers so they heat up right before you go in the bathroom and then time-out after that.

TIM: OK. So if I get this correct, you can just put a thinset concrete and then put tile right down onto the subfloor? Is that right? With the heating mat underneath?

TOM: Right. If it’s nice and smooth, you can do that to add heated bathroom floor. If it’s uneven, then there’s a number of ways to smooth that out, either through an additional subflooring material or by setting mud underneath it.

TIM: I appreciate your show. Thank you.