Electric Radiant Heat in a basement apartment
Hi, We’re thinking of converting about 400 sq. ft. of our basement to an apartment. We will turn it into an inviting space, but we will resist our usual temptation to overspend on materials. We were thinking about using electric radiant heat mat for the whole space, not just the bathroom. The headroom is minimal, and we want to preserve as much of it as possible. The house was built in 1905. We will add a dedicated dehumidifier to manage any water vapor coming through the walls or floor. A few questions: 1) Can we just embed the mat in a leveling layer of concrete and skip the tile? I’m assuming this would be cheaper than tiling, since the leveling layer is necessary. 2) I’m assuming that the mat would dry out any water vapor coming through the slab. Is that right? 3) Do I install a vapor barrier between the existing slab and the mat? Thanks, Miles
Replies
1) No, it will just chip and flake into a mess. It will be CHEEEEP though.
2) Heat, electric or otherwise, will not make moisture dissappear.
3) Vapor barriers go under the slab.
You have a few options, but need to answer a few questions. If this slab has no vapor barrier, probably has no insulation, right? You will be wasting a lot of energy.
On an uninsulated slab, you can put down 3/8" or 1/2" rigid foam, cement backer board, the electric mat in a layer of thinset and then tile over it. Else, use some sort of forced air. Just my 2c.
If you don't want to
If you don't want to "overspend", why don't you just use electric baseboards?
I agree w/ the other poster ... you do need a bit of an insulating layer under it. Not sure how much headroom you have ... are you talking 8 ft now or a lot less? Any radiant heat w/out insulation will be expensive ... like trying to heat the space while at the same time trying to heat the mass of the earth ... wow. Seriously try to get a layer of insulation down. You are NOT trying limit overspending if you are considering radiant floors. Choose carefully whatever you do ... you only have one chance, really. Are you being cheap or are you trying to be economical? There is a difference.
Would it be possible and/or practical to simply remove the existing basement slab and then re-lay a new slab with radiant mat and vapor barrier and insulation underneath?
There was an article in JLC recently about lowering your basement floor. This would entail breaking out your existing slab and digging it slightly deeper, but you also gain headroom, you can bury things if you need to, and you can properly insulate and set in an appropriate heating system.
Hey, thanks for the help everybody.
Miles