El. radiant floor heat w/end gr. floorin
My husband has a really crazy idea. We have a slab on grade floor with 8″ ceramic tile. He wants to put in electric radiant floor heat, and says he doesn’t want to raise the level of the floor. His plan is to cut out the grout joints with a wet saw that he fabricated out of milk cartons (?) and inbed the heat cable and grout it in with thin-set. Then he wants to rough up the glaze on the tile and mastic down end grain hard wood flooring that he spent all last summer making. Is he nuts or what? Could this really work?!!!!! Are 8″ centers too much for electric cable? What else do we need to know? The flooring pieces will be grouted with sanded floor tile grout. Are these going to shrink and expand and crack? Now we don’t want you to jump on the band wagon ’cause this is phrased like we think it won’t work. Think it through. The flooring pieces are all 3/8″ thick hard wood branch pieces that have been totally dried, soaked in a solution of 50% linseed oil, 50% mineral spirits for three days. Then they were totally air dried. The space between the pieces will be between 1/8″ to 1/4″. Is there anything we are not considering?
Your input is greatly appreciated – wife of ziptar or crowbar
Replies
Are you serious?....................................Iron Helix
"Wife of ziptar or crowbar"...
Hmmm...when you get stressed do you say "Mepps...Mmmepps!"<g>
Is electric heat affordable in your area? Do you know what your added electrical load will be? Does your service panel has space available to handle the extra breakers required?
Anyhow...it certainly is an interesting plan. Since you don't want me to tell you it won't work, I won't. But I will recommend that you not use sanded tile grout between the end-grain blocks. Either use the sawdust grout, or use a commercially available cork-based grout. Both will allow the wood to move without causing damage to the wood blocks or the grout.
If his wet saw consists of a water-filled milk carton with a hole to dribble water while running a regular old circular saw...he'd better be careful. Forget the water, spend $40 on a 7 1/4" dry-cut diamond blade, tarp off the adjacent rooms, set the saw depth for whatever he wants (3/8ths?), and cut away. The diamond blade will make short work of the grout. It'll be as easy as cutting wood...though a bit messier.
So it's not a hoax!..............:>)
Here's my two cents. Usually electric radiant in floor heat is used as a secondary "comfort" source and needs a primary heat supply to be effective. And 8" on center seems two far apart to give enough radiant heat.
The grout cutting will put dust by the pound everyplace in the house!
And as Mongo asks.....check out the electrical situation for capacity and for calculations of possible cost of consumption. For our area electrical heat is very expensive compared to gas!
Would it be easier to remove the tile and thickbed a heatmat or embed radiant water tube in 2" of concrete over the top of the existing floor?
If you pull it off................WOW That IS AMAZING!!!!
Best Wishes..........................Iron Helix
Iron Helix and Jay both address the spacing of the cables. It's reason to worry. You could cheat somewhat by removing all the grout, in both directions, and running the the cable in a grid pattern, both in the "x" and "y" axis.
You'd need to do two things. Find out if the manufacturer allows the cable to be crossed, and find out what minimum bending radius is allowed for the cable. I'd venture that they'll not want the cables crossed, and that they won't allow/recommend the cable to be bent in a severe 90 degree turn found in a tile pattern.
One last item. Electric radiant is really intended for use under tile. It just doesn't have the BTU ooomph to give adequate heat through wood flooring, especially in an unconventional setup like this one. Still, it maight take the chill off the floor, but it's unlikely you'll get whole-house heating performance out of this.
Though overall the idea is not likely to give great heat, I love the unhindered thinking involved in dreaming this up. My compliments to the two of you.
One of the brands of the mat style has both 10 watt/sq ft and 15 watt/sq ft systems.
The lower wattage one can be used under vinyl.
Look here http://www.warmlyyours.com/prof/products/productroll_vinyl.asp
Then look at the floor option on the upper left. They have systems for wood, laminate, and carpet.
None of them will for this guy, but just an FYI for the future.
Bill,
Thanks for the info. I'll try digging into the link this weekend.
I put down radiant heating mats under slate in my bathrooms. I think they are a great idea. I noticed that in the mat that the wires are only 3" to 4" apart. It seems to work fine, no cold spots anywhere in the slate. I don't know if 8" is too far apart or not, but you might check out this website:
http://www.wattsradiant.com
I used their electric heating mats and my wife, kids, and cat love their warm floors.
Good luck with your remodel.
Crowbar,
I put down an electric cable floor heating system in one of the bathrooms in my house, 800w, (requires a single pole, 15A breaker) aproximately 60 square feet heated area. The manufacturer's (Maxxon) installation instructions included templates for 6" and 4" spacing of the wires. At the 6" spacing that I used there are noticeable hot and cold spots (actually lines) on the floor, but I use it only to take the chill off the tile. Because the electric versions of RFH are seldom installed with enough thermal mass to evenly distribute the heat, and because the output of the wire is limited, spacing over 6" is not prefered.
I agree that sanded grout and wood end cuts are a recommended combination. The wood floor idea will work, with that exception. The electric heating idea as you decribed will be marginal at best but most likely dissappointing.
Tim