Heating Systems

Discussion in 'Ceramic and Stone Q&A' started by brenfan, Dec 23, 2014.

  1. brenfan

    brenfan New Member

    Good Day,

    Merry Christmas.

    I am new to this forum and have a simple question. I have not seen a direct answer to this so I will put it out there.

    I purchased a heating system here:

    Electric Floor Heating Cable Systems with Floor Sensing Thermostat

    This will go in my basement bathroom. Heating systems/ditra/porcelain tile.

    My only question is, I only need the obvious areas heated (foot traffic area). When I lay the cabling, and don't lay it under the vanity or behind the toilet etc. Will the ditra be warped/have any variation because of the cabling?

    I am assuming as the thin-set bed goes on before the ditra it will just level out between the wire but I was hoping for some clarification.

    Thanks guys,

    Happy holidays.
  2. Mike Antonetti

    Mike Antonetti I Support TFP Senior Member

    Bud ? No, not for you, the guy's name.
    Wire goes on top of ditra, not under, what size tile? Just check your lippage, use minimum 3/8" notch trowel. Bud should be along for more specifics.
  3. Bud Cline

    Bud Cline Tile Expert Charter Member Senior Member Published

    A little friendly advice from a "been there done that guy". I would install the cable, then cover it with Self Leveling Compound. This SLC then becomes the required thermal-mass that will distribute the heat evenly. On top of the SLC would come the DITRA but DITRA would not be a requirement. DITRA will however offer some protection from cracking tiles as the floor components shift seasonally or when the heat from the system comes and goes.

    To try to install DITRA directly over the cables using only thinset would be a big mistake in my opinion. It just isn't that easy to do and you are exposing yourself to damaging wires from using the trowel to apply the thinset.

    To cover the cables will require 3/8" of SLC. Don't forget to primer the areas to be covered with SLC.

    I know the [heat] instructions say you can do what you propose (install the cables in thinset) but, my advice to you is DON'T DO IT. It's not as easy as they make it sound.

    The heat will not warp the DITRA.
  4. brenfan

    brenfan New Member

    Thank you for the feedback. I was reading the instructions and I thought it would be tough to in-bed the wires directly into the thin-set and immediately place the ditra on top.

    Thanks a bunch
  5. Bud Cline

    Bud Cline Tile Expert Charter Member Senior Member Published

    NO-WAY you can do that. It doesn't work like that.
    Thinset is very sticky and not trowel-friendly under those circumstances. You would never get the thinset smooth enough to get the proper contact/attachment to the DITRA and be able to crawl around on top of the DITRA at the same time. Thinset is formulated to be spread with a notched trowel and then have tile impressed into it. Any attempt at trying to make the thinset thicker than what would be combed onto a smooth surface would be a waste of time.

    SLC is the way to go.

    How many square feet are we talking about?
  6. brenfan

    brenfan New Member

    50 sq feet or so. And I agree. Thinset is way to thick to work with. I will self level!
  7. Bud Cline

    Bud Cline Tile Expert Charter Member Senior Member Published

    Okay...so three bags of SLC, you won't be sorry you did it that way. Don't forget the primer.

    Keep the cables away from the toilet flange. The cables have the ability to emit heat outward about 1-1/2" in all directions but you still want to keep the cables about six inches away from where the toilet seal will sit.

    Dam all possible egresses so the SLC doesn't get away. I usually use a one gallon paint bucket caulked to the floor to temporarily barricade the toilet flange. The bucket will easily break-away after the SLC has had time to set up. I also use foam sill-seal up the walls to stop the SLC from running up tight against the walls, you need an expansion gap at the walls.
  8. Mike Antonetti

    Mike Antonetti I Support TFP Senior Member

    So he's eliminating the Ditra?
  9. Bud Cline

    Bud Cline Tile Expert Charter Member Senior Member Published

    Don't know!
  10. Mike Antonetti

    Mike Antonetti I Support TFP Senior Member

    I assumed he was going to put wire on top of Ditra and self level, then thinset, wires (heat source should be above mat. Guess that's why Schluter had to come out with their own tile warming system.
  11. brenfan

    brenfan New Member

    Hey guys.

    Many people recommended setting the cables, using thinset to cover the cables and cover with ditra while wet. Then tile on Ditra. I didn't really like this method so I wanted to come on here and check.

    Now I am going to cable, SLC, Ditra, thinset/tile.

    Seems like a better idea.

    Thanks again.
  12. Mike Antonetti

    Mike Antonetti I Support TFP Senior Member

    Yeah there's some contradictions when you add all those systems.
  13. Bud Cline

    Bud Cline Tile Expert Charter Member Senior Member Published

    Mike brings up a good point. I spaced it off but that's because "I'm losing-it".

    DITRA has introduced their own floor heat mat that gives you the best of all worlds. The DITRA mat is specially designed to receive the heating wires they offer in their DITRA Floor Heat Kit.

    The reality is the DITRA Mat will also work with the heat systems offered by some other manufacturers. The heating system you have already purchased may well work with the (specialized) DITRA Mat.

    I just installed my first one a few months ago and the system is great. I used Warmly Yours heat system with the DITRA Heat Mat and it worked great. It would completely eliminate the need for using SLC and would get the heating elements closer to the surface (not that that matters).

    You could check with the maker of the cable system you have purchased to be sure it would be compatible with the DITRA Heat Mat product but I think it is.

    Good call Mike...I completely spaced-off the DITRA possibility.
  14. Mike Antonetti

    Mike Antonetti I Support TFP Senior Member

    I'm just trying to keep up with these heating systems, one day I may need to lay it down for a customer, the other day my wife said in kitchen one morning the tile is cold, I was quick with my response to put some socks on, no need to tell her about this till I'm ready to tile the floor when she says she doesn't like tile cause it's "cold".
  15. HS345

    HS345 Pro Member

  16. Mike Antonetti

    Mike Antonetti I Support TFP Senior Member

    I think nu heat or one of those companies said wires go nearest to surface, so a little controversy, still 0 installs for me though.
  17. Bud Cline

    Bud Cline Tile Expert Charter Member Senior Member Published

    Exactly correct.
    • Regular DITRA - heat system under the DITRA.
    • DITRA HEAT - the wires go on top.
    • DITRA HEAT (Mat) is different from DITRA Mat, two different products, two different profiles, two different primary purposes.

    So now there are actually THREE DITRA Membrane (Mat) products on the market.
    1. DITRA 1/8"
    2. DITRA 5/16"
  18. Seventwenty

    Seventwenty Pro Member

    What is the "R" value of Ditra? Will it act as an insulator and reduce heat transmission?

    I guess I don't see the need for the Ditra if pouring over the heat system. I always create a "border" using Dense Shield, layout the heat inside the borders, and then pour. When finished you have a substrate approx. 5/16 thick. If a thicker base is preferred then use 1/2" DS.

    I'm not saying that using the Ditra is wrong, I just haven't researched it. As for setting the system in thin-set, did it the 1st time, never again.
  19. Bud Cline

    Bud Cline Tile Expert Charter Member Senior Member Published

    Have no idea! Don't know, don't care, doesn't matter. I seriously doubt it qualifies for any kind of an R-Factor.
  20. kylenelson

    kylenelson You'll find me on the floor I Support TFP Senior Member

    Schluter makes a mat that has specifically spaces knobs built in to it to click the heating wire in to. Definitely runs the wire on top, but I'm not a tile guy so I will stop there.

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