Slate Tile Flooring Over Radiant Heating
I am a new contractor in the Lake Tahoe area. I am planning to build my home the coming season. My wife has chosen slate flooring for the entire house and I have chosen a radiant floor heating system. The typical method is using gypcrete to embed the tubing and then the flooring over that. Elsewhere on the internet I have heard that gypcrete is not a good underlayment for tile or stone flooring. Is this true?
I would like to have a decent heat mass. Could I apply a mortar bed over the tubing instead of gypcrete and the tile over that? The plumber called out 1/2″ Wirsbo tubing. How thick would the mortar bed have to be?
Wirsbo has a product called Quik Trak. The Quik Trak has grooves for the tubing. Can you apply tile with thin set right over the Quik Trak? Has anyone experienced using this stuff?
Replies
Myci- here's a link to a discussion of gypcrete, radiant heat and tile.
Another discussion on mudbed vs slc.
The short version is that, yes, a mud bed would be much better than lightweight.
Try posting your Quik Trak question there, too. Seems like someone did an installion over a similar product.
...up north attitude...
If you plumber is spec'ing 1/2" PEX tubing, make sure he is using it in 150' (not 300') loops. For the arguments why, look down in "Energy/Venting/Heating Folder for the "Heating with a wood stove" thread.
David Thomas Overlooking Cook Inlet in Kenai, Alaska
Thanks for the heads up on the Pex diameter/length discussion. Very interesting- I'll pass it on to DH, who's doing the plumbing.
View Image...up north attitude...
What's slc? s_____ lightweight concrete? I'm being dense.
I read through most of that till I lost track of which page I was on. I noticed the part where someone recommended against a floor radiant system entirely--radiant heat as supplemental heat only? I was trying to not interpret other advice based on that statement, which I disagree with completely.
I look at this as there being many correct solutions. The recommendation you get will depend on the crowd you speak to at that moment. They can all be right based on their experiences.
Our bedroom level floor is gypcrete. It's on a base of 3/4 ply over 14" tji's 12" oc. That creates a really solid structure with little movement. The tube was nailed to the subfloor with special fasteners. A bonding agent was sprayed before the gyp poured. We let the gyp dry to 5%. We applied an anti-fracture membrane recommended by Maxxon (they reasoned that the gyp bonds so thoroughly to the substrate and the tile that any drying/settling cracks in the gyp would telegraph and crack the tile.) So I used the AFM and installed the tile with thinset. Worked well for us thus far. Can only speak for the first two years and won't predict the future.
The gyp does help substantially with soundproofing. The mass is fine, but nowhere near the staying power of my 8" concrete slab (measure the heat retention in hours vs days).
If I had to do it over, I'd look into Warmboard for the following reason. Our structure is really tight and efficient, despite its size, so the mass of the main floor slab is sufficient to heat the whole house mostly. On the few really cold days (<20), I'd want to give thee bedrooms a quick jolt of heat at bedtime and could get instant response rather than the few hour ramp-up of gyp or slc(??) or concrete. Don't know if I'd choose it, but I'd look into it.
On the 1/2 Wirsbo, David Thomas and I just discussed that in GORY detail. Well, I asked questions and he answered. There are few people who's advice carry's more gravitas for me. Look for the thread in the Energy folder about Wood Furnace for RFH. The discussion starts about halfway into that thread.
Jim, that's Self Leveling Cement.
We did convince John, a Texas native, that radiant heat was a good thing. Gypcrete with Ditra membrane was the way I originally planned...
View Image...up north attitude...
Got it. I lost track before y'all convinced him.
So Ditra's an AFM then, I guess. My gyp is 1 1/2" btw. With any cementious product, including SLC, I'd be concerned about getting a really level base for the tile/wood. I've used about five bags of it in another area of the house, and while great for the purpose, it still didn't get the same level as troweled concrete or gyp. I _hate_ tiling over a base that's not perfectly level.
But again, there are likely several right answers.