I have built a home in Montana w/ radiant heat flooring (hydronic/hot water pipe), and covered it w/ lightweight gypsium substrate. It is an engineered I-Joist floor system w/ 6 mil visqueen, the radiant hose and the gyp underlayment. It was done approx 3 years ago, w/ no evidence of cracking and/or expansion. I have installed some of the flooring, including Junckers hardwood floating floor, carpet, and floor tile(ceramic).
Recently, a tile contractor said I must use a ‘fracture membrane’ when installing tile or stone over radiant heat flooring. To date the areas I have tiled have no evidence of cracking or lifting. I’m getting ready to install both ceramic and stone floor coverings in several bathrooms and the kitchen. I’ve installed alot of tile over the years, but most has been over concrete slab or conventional raised foundations. I do not have experience w/ radiant heat floors, as most of the homes I’ve built are in the So. Cal. area. The existing flooring has minimal deflection, and is a solid platform.
Do I need a ‘fracture membrane’ for a radiant heat/gypsium floor? Thanks, John
Replies
Yes, you need a membrane. Use Ditra
Schluter makes one; it can also be used to beef a sub-standard floor so the tile won't crack. Stuff like this in complex installations under tile--which is so permanent--comes under the heading of 'cheap anti-callback insurance'...even if it costs a bundle, it's cheaper than you having to tear it out and re-do it later.
I have seen tile hold nicely for two, three, four years, then start to crack everywhere; fine hairline cracks you don't see until someone spills talcum powder or cake flour on the floor--then it looks like a spider web and you're in dutch....
Dinosaur
'Y-a-tu de la justice dans ce maudit monde?
Cloud should have something to say as well.
He has excellent advice, as well as first-hand experience, with installing and living with what you're asking about..