Contractor Talk - Professional Construction and Remodeling Forum banner

Anyone ever used electric heat under tile…

4K views 35 replies 15 participants last post by  Warmsmeallup 
#1 ·
Outdoors?

We want to melt snow on a patio.

Any thoughts? Any recommendations?
 
#3 ·
Emailed Schluter yesterday and got a wimpy response:

“At least at the moment, seeing that the product is so new we do not have any installation methods or ratings for Ditra-Heat outdoors.”

I read that as “Huh… Never thought of it, but since it’s never been done – we can’t help you!”

I guest I’m also questioning if we can deliver enough heat to melt snow with electric heat. When we do it with hydronics, the boiler puts out water at very high temps.
 
#4 ·
My thought would be that it might only melt it enough during the day to make it really slick at night when it's colder. Can you get a stat that goes low enough so that it doesn't run all the time? I would suppose so.

I see no issues with installing it outdoors.

We've put them in showers for years but they are always covered with kerdi.
 
#6 ·
Heated drive ways are not uncommom in CO, I have a customer who's drive way and garage floor are heated, BIG pitch in garage floor drain in the middle comes home suv packed with snow, gets up next day no snow and a dry floor. I can not be 100% but i think his system use's hot water on a recurculateing line.
 
#8 ·
I have a client that had one at a house not far from me. Really steep laneway, damn thing had a monster electrical service. I remember asking him if it cost a lot to run and his answer was "what other choice do I have?".

I have seen dozens of patios, porches and laneways with ice-melt using glycol loops.
 
#12 ·
I'd hate to think what the electricity bill would be for something like that (though we often pay a lot for conveniences in many other aspects of life so why not).

I'm only used to doing hydronic systems in such scenarios (the last setup we did was to de-ice a set of concrete steps going up to a house). Not being familiar with electric heat outside of heated floors, one of my few concerns is that it would be about as effective as those heating cables people string up/zig-zag along there eaves to melt ice build up.

Additionally, there's always the concern of what's happening to the wires and connections after going through a few freeze/thaw cycles.
 
#17 ·
Long overdue update. We decided to go with the WarmZone product. We had to cut kerfs in the concrete ¼” wide x 3/8” deep, 2-3/4” apart (2690 LF of kerfs). This is not a job I would wish upon my worst enemy (ranks in the top five worst things I’ve ever had to do).

Once the kerfs were cut the installation is pretty easy. If you’ve done a bath floor, it’s pretty much the same concept – just bigger gauges and lots more electricity.








Here’s a pic of the finished project.





It has worked every snow we’ve had. We had 12” of snow in 24 hours last week and the system melted it as it fell – no snow ever accumulated on the deck.



WarmZone review:

The product is pretty solid and initially WarmZone’s service was good. They designed the system and put all needed components in the package. Their service fell off incredibly when we ran into problems.

Problem #1: Once the kerfs were cut and the wire laid, WarmZone requires an epoxy to be applied over the wiring. We wanted to use a self-leveling product (LevelQuik), but they said no. So we did the epoxy thing. Problem is: the thin set would not adhere to the epoxy. WarmZone stopped returning calls when we ran into the issue.

Problem #2: The leads for the WarmZone are a large gauge and the lugs in the panel they supplied were designed for considerably smaller AWG wire. WarmZones solution was to simply untwist the braded wire and cut some of the braids off – re-twist and connect. They claimed this was the manufacture’s recommendation. We asked for this in writing and they stopped returning our calls again. We ended up having to redesign (between our electrician and the building department) and replace some of the panel guts.

If I had to do this again, I would look for someone stupid enough to do the kerf cutting and find a different supplier.
 
#32 ·
Long overdue update. We decided to go with the WarmZone product. We had to cut kerfs in the concrete ¼” wide x 3/8” deep, 2-3/4” apart (2690 LF of kerfs). This is not a job I would wish upon my worst enemy (ranks in the top five worst things I’ve ever had to do).
DaVinci,
Well, I don't mean to close the door after the horses are out but you could have saved considerable cost on the materials and labor. Though cutting "kerfs" , we call them slots, into the concrete is still required, cutting them at 4-5" spacing in that application would have worked just as well without wasting a lot of energy.

Next, and most important, if you filled the slot with a 1/4" backer rod 3/8" shy of the surface, you could have just run the SLC right over the slots. I don't know why your supplier required that you use "epoxy". If your product had the Danfoss name on it, we are a direct distributor for the same manufacturer and the word "epoxy" isn't anywhere in the installation manual for concrete applications. We only recommend using expansion joint filler and that's only when the slots are to be exposed as the finished surface.

I will agree that the cutting of the slot is one of the nastiest jobs on the planet (try doing it in asphalt) and we prefer not to do that work. We paint the lines and then we sub the work out to concrete saw cutters and have them include the vacuum cleanup. It's well worth the extra cost.

NEVER, absolutely NEVER strip some of the wires from the cold leads "to make them fit" the contactor. The wires are sized based on current (amperage) draw. Decreasing the wire diameter by removing some of the strands seriously increases the chance of fire, to put it mildly!

Sorry you had a bad experience. If you have any questions, please feel free to email. We don't just sell the materials, we install them too. So the information you get will be from installers, not...something else.
 
#18 ·
Glad to hear it's working well for the client. The hydronic systems I have been part of hard thermal breaks installed below the slab. I will be doing new flatwork at my home this summer. Having steam heat, this electric option might be worthwhile, rather than adding a dedicated boiler for the melt system.

Was any slip sheet used over the slab, or did you tile directly onto it?
 
#22 ·
After testing several products, we ended up using a primer. I don’t remember the name of the product, but when it dried it felt like 40 grit sandpaper.

My tile setter would know the name of the product, he’s said he’s used it several times over strange/nonporous substrates. He purchased at the tile/stone supplier, so I think it’s pretty much a standard for them.

If needed, I can call my guy and get the name.
 
#26 ·
I did but it was in radiant (pex) driveway, porch to kitchen and through out the 1st floor.

I wanted to do it on my own side walk it's 100 x 12 but the gave the block / street new sidewalks on the house. glad I didn't.

It worked great. Only used the electric stuff in bathrooms and bedrooms above the garage or a cold part of the house.
 
#34 ·
Now I understand why they made you cut them in 2-3/4" apart. If you only cut 3/8" deep. If you don't sink the cable in at least 1" -1-1/2" deep, they will not have enough depth to heat outward to meet the cable's heat next to it. We cut 1-1/2" deep and space them 5" apart. That would be 1/2 the materials, 1/2 the running power, 1/2 the running cost.

Yea, it took us some time to find a reputable cutter who took pride in their work. They charge us about $1.50/ft including cleanup and they take the slurry with them. It's 1/2 that if we have a way of digging hole and burying it.

www.comfortradiant.net
www.danfossradiant.com

I'm russell@danfossradiant.com
 
#35 ·
The slab is only 2” thick. At an 1” or 1-1/2” we would have cut through a lot of rebar and wire mesh.

At $1.50/ft., I would have been on that like a hobo on a hot ham sandwich! At $1.50 a foot, I would drink the slurry to get rid of it :laughing: The one proposal I got was close to $4/ft.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top