One of the best upgrades for a bathroom or kitchen tile floor is the use of in-floor heating. There are several different products available to accomplish the coveted ‘warm tootsies when it is forty below’. One of the more popular products (around here, anyway) is the Suntouch WarmWire radiant in-floor heating. That’s just a really long term for wires that heat your floor (and warm your tootsies).

Now that I’ve used the word ‘tootsies’ twice in one paragraph I believe it’s time to move on.

As an ‘official’ reference the manufacturer’s installation guide can be found online in one of those fancy-ass pdf thingies HERE.  It contains all sorts of things that you need to be aware of before starting your installation. While this post will walk you through how I do it, your installation may differ in aspects of which you are unaware. You need to read through the manufacturers information as well before you actually install you WarmWire.

This is as close as I’ll ever get to an official disclaimer: Be aware that the methods I use will differ somewhat from the manufacturer’s instructions intended for the do-it-yourselfer. I am a professional tile guy (really – what are you laughing about?) I accept liability with everything I touch in a customer’s home and accept that risk with the methods I choose to utilize. Read the manufacturer’s instructions before installing your WarmWire!

This information focuses on the installation of the substrate below the WarmWire, the installation of the wire, and the installation of the Schluter Ditra membrane above the wire for the purpose of tile installation. The technical aspects of the electrical wiring are covered only briefly and in very basic terms. They are not meant to be a definitive guide to properly wiring the WarmWire underfloor heating element to your control box and power supply. READ THE MANUFACTURER’S INSTRUCTIONS REGARDING YOUR PARTICULAR CONTROL BOX! In English that means if your house blows up it isn’t my fault – I was all the way over here.

In your area it may be required to have an electrician wire your heating element. Check with your local building codes to make sure. If it’s required and you don’t do it you could be in heaps-o-trouble. Don’t mess with the city codes, they’re not very nice if you piss them off. Trust me on that.

Ass covering over – lets get on with it.

The WarmWire system consists of two basic elements – the wire and the control box. The control box is hard-wired to your house’s electrical system and the wire is attached to the control box. The wire is then routed down behind the wall and under your floor. After installed you can essentially control the temperature of your floor tile with the control box.

Before you begin you need to figure out how much WarmWire you need to purchase. The above referenced pdf contains a chart which will explain which wire you need based on the square footage of the floor in which it is being installed. There are three different spacings which can be used and utilize different wattage per square foot. That’s all just confusing crap so I’ll explain it like this: The closer you place your wire the warmer your floor will be – and the more power it will use to accomplish that. Easy enough, yes?

How long your wire needs to be depends on how much square footage you’re heating. The quick way I figure it out is the square footage of the room multiplied by 0.90 (because there is no need to heat along the walls, in closets, etc.) and multiply that by 4.7. That will give you the approximate length of the wire you need.

The wire is available in pre-measured lengths. It is not something you can just order to a specific length. It is a closed loop wire which means it is one complete unit and not a wire that can be cut to length. So you need to figure out the length and order the closest to that number.

The different spacings are 2, 2 1/2, and 3 inches. For the purpose of this post I will use the 2 1/2 inch setting as that will be the most commonly used – and because that’s what I have photos of.  You need to also purchase the wire straps which will attach the wire to the floor and hold it in place while you install your flooring above it. Do not use nails, screw, etc. – use the straps. They have pre-spaced clips to hold the wire in place correctly. And using any other method you risk damaging or severing the wire.

For this particular installation I chose to use 1/2″ Hardiebacker cement board on the floor with the heat wire installed to it. Above that I used Schluter Ditra membrane for the tile substrate. When using Ditra you want your heating element, whether it be the wire, a mat, or other type, beneath the Ditra – not between the Ditra and tile.

You can click on any of the badly taken photos for a full-size version.

Installed Backerboard Substrate

Figure 1

Make sure your Hardiebacker, or whichever substrate you use beneath the wire, is installed correctly for a proper tile installation. This is imperative since it is the very base layer for your floor. If not done correctly you risk compromising the entire installation – pay attention, this gets expensive! Read How to Properly Install Backerboard for Floor Tile.  Check out that link – I’ll just sit back here and have a beer Pepsi while you do.

Allrighty! (I can’t believe I just typed that) The first thing to do (after properly installing your substrate – in this case hardiebacker – figure 1) is to install your straps. The metal straps made for WarmWire have tabs every inch. I’m certain you can figure out how to use them for whichever spacing you’ve chosen.

Installing WarmWire Straps

Figure 2

Installing WarmWire Straps

Figure 3

For this particular installation I’ve used every third tab in some areas and every other tab in others. I do this to make the floor warmer in certain areas (in front of the shower and tub) and less so in other areas. I do not know if this is standard practice or not – it is for me. If you are concerned about it please see the ‘disclaimer’ at the top.

The straps are placed on the floor and screwed down. (figures 2, 3)  Suntouch recommends using a spray adhesive to hold the straps in place until you get them screwed down – I do not do this.  I have no problem keeping them where they need to be without it and I do not like any foreign substances beneath my tile installations, especially one to which thinset may or may not adhere.

Close-up of WarmWire Heating Elements and Straps

Tab Spacing

I place the straps every four feet to hold the wires in place. I find this gives me enough hold for what I need to do above the wire before the mortar is fully set. Once that happens they won’t go anywhere anyway. But you do need them to be held in place until that point. Don’t try to use a shortcut with this part, if you damage the wire you’ll need to 1. pay to replace it and 2. start over. Neither of which are my preferred method.

You may want to invest in the electronic box Suntouch makes called the ‘LoudMouth’. It is a small electronic box with a 9 volt battery which you hook the wire to when you start your installation. If you damage or sever the wire at any point the box will scream obscenities at you, call you names, light your dog on fire, or something that will let you know in no uncertain terms that you have screwed the pooch (hopefully not while it was on fire).

If you do damage the wire you can purchase the splice kit with which you can repair the damaged wire. I’ll cover that in another post – hopefully one nobody will need to read.

The end of the WarmWire which is attached to the control box is twice as thick as the heating part of the wire. You need to start your wire placement at the base of the wall beneath the control box. Unroll the WarmWire until you get to the smaller part of the wire – the heating element – and place that part of the wire at the base of your wall. In basic terms you do not want any of the thicker portion of the wire beneath your floor – only the thinner part.

Now the fun part. Starting at the point at the base of your wall start stringing the WarmWire back and forth across your floor utilizing the proper tab spacing for your wire distance. In the close-up photos I have it installed in every third tab. Place the wire beneath the correct tab and push it down to hold it in place. DO NOT use a hammer, screwdriver, or beer bottle Pepsi can to pound or push the tab down.

Installing WarmWire Heating Elements

Figure 4

Installing WarmWire Heating Elements

Figure 5

You want to start at one side of your room and end at the other. You NEVER want to cross the wires over one another. They need to remain a minimum distance of two inches apart at all points. Plan accordingly. This is why you want to get your layout figured before you start.

This is tedious but take your time and get it correct. It is imperative for proper performance of your WarmWire.

Installed WarmWire Heating Elements

Figure 6

The end of the WarmWire is a bit thicker than the wire itself. I will usually take my knife or a screwdriver and cut a small groove into my backerboard or subflooring in which to place the end. Ideally you want the end of the wire to end up at a wall in which case you can simply tuck it between your backerboard and the wall footing (you left a gap there, right?) but sometimes you need to end it in front of your vanity or tub.

I do the same thing with the probe. There is also a temperature probe which must be placed beneath your tile to regulate the temperature. It is thicker than the wire itself also. You can simply cut a groove out of your subflooring in which to place it.

Installed WarmWire Heating Elements

Figure 7

Once you are finished stringing the WarmWire over your floor you need to take care to not abuse it. You can walk on it but don’t dance on it, know what I mean? Take a break – you deserve it. When I sober up post the remainder we will cover how to install Schluter’s Ditra tile membrane over your Suntouch WarmWire for your tile installation.

{ 96 comments… add one }

Leave a Comment

  • Leighsa

    Hi Floor Elf,

    I am remodelling my 2nd floor bathroom in a 1930’s house in Toronto. Every time I have a question, Google brings me to your awesome blog!

    We are putting down 12″ x 24″ cararra marble tile over floor heat cable (NuHeat) and I want to make sure that we have the correct subfloor layers. Our house has wooden joists, 16″ on centre. The current subfloor is 3/4″ plywood. The contractor wants to thinset the Ditra directly over the plywood, add a layer of thinset, let it dry, then install the NuHeat cable, then thinset and tile.

    Everything that I have read says that the cable floor heat (not a mat) should be below the Ditra.

    My questions:

    1) Does it make a difference if the floor heating cable goes below or above the Ditra?

    2) Do we need a 1/4″ or 1/2″ cement board layer before the heat or Ditra?

    Many thanks!

    • Roger

      Hi Leighsa,

      1. Not in the way it heats, but it makes it significantly easier to install the tile and get it flat. It can be done the way he wants to do it, it won’t hurt anything.

      2. No, you don’t need cement board.

  • Jeremy

    Hi Roger,

    Could you give some advice on a good method to embed suntouch wire into the shower mortar bed? I started out carving a channel into the mortar with the corner of a chisel, but am hoping there’s an easier and faster way that won’t ruin more chisels :eek: Thanks!!

    • Roger

      Hi Jeremy,

      A rotozip with the large tile bit works very well through deck mud.

      • Jeremy

        Thanks! Just to make sure – embed wire completely, hot glue in spots to hold in place, thinset over?

        • Roger

          Hi Jeremy,


          Sorry for the delayed response, my spam filter went ape shit last week for some reason, I just found your comment in the spam folder, I hope the answer found you in time.

  • Shannon

    We are renovating and expanding our master. Is floor heat worth the extra money? What is the expected life of the heating system?

    • Roger

      Hi Shannon,

      Absolutely it is! Most systems, when properly installed, will last at least 20-25 years with normal (seasonal) use.

  • Bill


    Great website!

    We are in the process of remodeling our master bath. This will be the third master bath that we remodeled and we wanted to kick-it-up-a-notch and use Suntouch under a marble tile floor. We have slab concrete here in Texas and I was happy to find your website.

    So we will consider putting down cork, then the WarmWire, then the Ditra, then the marble tile.

    My concern is possibly creating too much flexibility with use of both cork and Ditra. Would this cause the multiple layers of thinset to crack under normal use? Do you have a recommended thickness of the thinset to keep this from happening?


    • Roger

      Hi Bill,

      You will not get vertical compression from the ditra, it is designed for lateral movement. So, while you will get a TINY bit of movement from your thermal break with the cork, the ditra will dissipate that before it gets to your tile as well as allowing lateral displacement. Your plan is solid and that is the correct way to do it.

  • Mark


    I am renovating a bathroom in a wood frame house. I am intrigued by the under floor carbon film heating systems available. They all say install the tile above the heating film per manufacturers instruction. Several also suggest installation over a thin layer of non-metallic insulation faced. I have a concern though, most of the films are anchored to the substrates periodically, not bonded and they require waterproofing over the top, I’m thinking they mean a sheet membrane product, probably PVC or CPE.

    I was planning to use Kerdi sheet until this heating notion popped up. Is it OK to lay tile over this “loose-ish” layer of heating film ?

    • Roger

      Hey Mark,

      Kerdi and products like it are exactly what they are talking about. Kerdi is perfect. However, I would lay the heating elements in a full bed of thinset, then install kerdi over it. That is the only way to get proper support beneath your tile. The elements need to be bedded.

      • Mark


        Thanks for the help. Just to be sure, the heating product I am looking at is a stiff film, it is water sensitive and it fully separates what is below it from what is above it. Its not like wires or mats that are mechanically engaged by a bedding material.

        Here is a link to an image.

        • Roger

          Hi Mark,

          That’s understood, but if you install tile over it everything below it must be bonded to the layer below it, heating mats included. Whether that is something as simply as a full-contact adhesive for the mats, or a layer of thinset below it, it must have full contact. You can not place tile over a substrate which has only periodic bonding to the substrate beneath it. Even ditra has full contact below it, the tile is mechanically locked into it with a full layer of coverage beneath the tile.

          Have you contacted the manufacturer about installing tile above it? If they say the periodic contact is fine and are willing to warranty that, contact schluter and see what they say about it. It may work perfectly fine, I am not familiar with that particular product. I just see where problems may arise with a layer not fully embedded.

          I could be wrong – that happened once. :D

          • Mark

            Me too, once!

            I suppose it is time to pick a source and pursue some answers. I might be pioneering here; there doesn’t seem to be a lot of installations in the US. One source only sells this stuff for under laminate floors while another with a suspiciously similar looking product says its good for tile. I’ll post if I find anything useful.

  • Michael

    Great site.

    I am installing WarmWire in my basement bathroom over a 6-year-old concrete slab. Should I install a cork underlayment for a thermal break, or would the RedGard paint product be sufficient? I would then install the WarmWire straps and wire atop that, the Ditra and then the Tile (per your instructions).

    • Roger

      Hi Michael,

      Redgard is a sufficient thermal break, although cork is a better one.

  • Rod

    I am finishing a lower level bathroom and have a couple questions after reading your series on installing electric heating cables.

    First, the subfloor is concrete, and there is a crack running diagonally across the area to be tiled (which measures about 5′ x 7′). The floor is about 8 years old and the cracks have been there since nearly the beginning. My current plan, based on the advice of a local flooring shop, is to install Pro Spec Flex-Guard over the crack, followed by a quarter-inch thick layer of cork as a thermal break. I’d then install the heating wire over the cork, embedding it in thinset, followed by an isolation barrier and finally the thinset and tile. Is this combination correct? Should the cork be adhered to the concrete in any way or is it supposed to float?

    Second, the local box store carries an isolation barrier called Homelux GatorGold. It appears similar to Ditra. Are you familiar with this product, and could it be a suitable substitute?

    Thank you in advance for your help.

    • Roger

      Hi Rod,

      That is the correct order and combination. The cork should be bonded to the concrete. Yes, gator gold is a suitable substitute.

  • bryan

    I need to raise my floor 7/8 to make the stairs meet code. Deck mud is far more economical than SLC so I’m looking for some advice on using it and embedding some electric heat cable. A 3 year old concrete floor is the base. There’s no cracking in it whatsoever. The manufacturer of the electric heat cable doesnt say anything about using a decoupling membrane. Have you seen cracks develop in tiles even when the substrate is cured concrete with no cracks? What are your thoughts on embedding the electric cabling in a 7/8 bed of deck mud?

    Thanks very much!

    • Roger

      Hi Bryan,

      Yes, I have seen cracked tiles over a perfect slab. I’ve also seen perfect tiles over a slab that looked like cracked glass. My point is you never, ever know how the slab is going to react and move over time, nor how it will affect the tile bonded to it.

      You can embed heating elements into deck mud just fine. And deck mud will separate the tile from the concrete. It is the original uncoupling membrane. :D

  • Allison Smith

    Have you ever run warm wire every 4 inches instead of 3? We are using it just to warm the tile and not to heat the room. We ran a little short of wire and in part of the room used 4 inch spacing. What are your thoughts?
    Thanks for your help!

    • Roger

      Hi Allison,

      I haven’t, but it works just fine. It’ll just be a bit cooler in the areas that you run it 4 inches, but not by more than a couple degrees, likely not even noticeable.

  • Adam


    I have the distinct pleasure of doing a full bathroom remodel in a home with exactly one bathroom. Up until now, I have been able to work around this inconvenience by doing bits and pieces here and there. However, I am going to be starting the floor/in floor heating stage. As of now, I have a flat, plywood floor and am trying to determine the best route to proceed. I believe you recommend cement board, in-floor heating wire, thinset, ditra, thinset, tile/grout.

    Would, in my case, skipping the ditra be ok? Trying to avoid as down time as possible due to my beautiful wife being pregant and having a two year old daughter that has no boundaries. Thoughts/suggestions?

    • Roger

      Hi Adam,

      You actually don’t need the backerboard. You can go right over the plywood with the heating wire, then ditra and tile. If you want to you can skip the ditra. Given the choice, though, I would use the ditra and forego the backer.

  • Vince

    Hi Roger,

    We had in-floor heating installed in our bathroom in a new build. Within a couple months we noticed the floor moving and grout cracking. Also whenever we walk on the floor you hear crackling sounds like you are walking on glass. Do you think the builder did something wrong? I have having difficulty getting them to fix it.

    Help please?


    • Roger

      Hi Vince,

      There are several reasons that could be happening. The sound you hear is thinset cracking out. It could be because there wasn’t sufficient coverage under the tile, the floor was not properly built to support a tile installation, or the heating element was turned on prematurely. You normally need to wait at least 14 days, 28 is better, between installation of the tile and firing up the floor heating.

  • Micha

    When remodeling our tiny master bath last year, I installed the Laticrete 3ft x 5ft Floor Warming Mat. The resistance tested fine before and after tile installation, then it sat for several months :bonk: until I got an electrician out to run a new lines to the breaker panel for this an several other projects.

    I got a GFCI fault when the controller was turned on, and reset the controller did not clear it. :censored: I’m about to swap the controller out, but wanted to see if you had any additional suggestions while I have everything pulled apart.

    Thanks in advance! :rockon:

    • Roger

      Hi Micha,

      That is a logical first step if the resistance measured fine before, during and after you installed it.

  • sandra

    I purchased a new home, completed in December, 2012. The tile floor was not grouted properly so I removed and regrouted using spectra lock. Now it appears the builder layed the tile directly on concrete with no barriers and the thinset used to hold this tile directly to the concret is not holding the tile and the only thing preventing it from popping up is the grout. Some of these tiles are also discoloring and are getting multiple stress cracks.

    I know I must start from scratch and redo this entire floor, which is 2800 square feet. Since I must now remove everything, molding trim, toilets, kick boards , etc. I want to make sure the next people do the job correctly. I believe I need a thermal/moisture barrier, then heating coils, then thinset, then ditra, then thinset and finally tile. Please can you tell me if I am correct and give suggestions as to what brands. I will be having tile laid that looks like hard wood and I will be using epoxy spectra lock un sanded grout vthank you for any help you can give me.

    • Roger

      Hi Sandra,

      You should first have your slab tested for the amount of vapor dissipation you’re getting. The problems you are having sound like it may derive from either excess slab moisture or the tile being set while the concrete is still green (not fully cured). This will ensure that the thermal break you choose is adequate for your slab. When needed I normally just use redgard or hydroban as a thermal break, it isn’t a big issue around here at all, so I can’t really give you particular brands for that aspect.

      I prefer the suntouch heating element, Laticrete 253 or 254 under the ditra and 317 or 253 over the ditra (317 is unmodified). And yes, I know Schluter wants unmodified everywhere. That isn’t how I do it. Bad elf! :guedo:

  • Scott


    I am planning on using the suntouch wires in my basement. I’m just starting to research and was wondering I need to put down before I lay the wires? Do I need to put any sort of a moisture barrier or in a dry basement would I be okay to lay right on the concrete? Also, I was hoping use thinset to install the warmwire rather than the self leveler – do you recommend against this or have any advice on how to make this the most effective?

    Thanks for all of your help with this!

    • Roger

      Hey Scott,

      If it’s a dry basement you don’t need a barrier beneath it. It does, however, help the efficiency of the heating element as concrete tends to suck a lot of heat from the wires. A thermal break is always helpful, although not required.

      You can use thinset to either install ditra over it or level out the floor before installing, or even install directly over after you get the wires down. In part 2 I show how to install ditra over the wire but the technique works for either.

  • Ray

    Great, thanks. How does he keep the metal straps secured in the mud bed so that they don’t move around when applying the thinset?

    • Roger

      Thinset them down the day before, epoxy them down the day before, sometimes double-sided tape (normally included with the straps) works fine. Depends on how sandy the deck is.

  • Ray

    Great Site.

    My tile installer does what I think is referred to as a ‘mud job.’ Mixes some sort of concrete with sand and lays an inch or so of it over the plywood subfloor. (first he lays tar paper, then a metal lathe then covers with mud) My question is where does the Suntouch warmwire go? Above the mud, or between the mud and the metal lathe? If below the mud (i.e., directly above the lathe), doesn’t it waste a lot of energy before it warms the tile?

    Thanks for your help.

    • Roger

      Hey Ray,

      Either in the top portion of the mud bed or between the mud bed and the tile.

  • Steve

    Great website! I am installing tile in a bathroom with 3/4 ply over 2×8 joists on 16″ centers and 12′ spans. I plan on adding 1/2″ plywood over that. Since I am installing warmwire cables, I was wondering if I can seal the plywood, install the cable and then use self-leveling cement over the cables to protect them and to level my floor which needs some minor leveling. The self-leveling would add about 1/4 inch.


    • Roger

      Hey Steve,

      Yes, but don’t seal the plywood. Use the primer for your slc, then install the wires, then pour the slc. Sealer will prevent the slc from bonding correctly.

  • Jim

    Hi Roger,
    Thanks so much for the awesome website and especially for the jackassery!
    The show so far:
    – 3/8 plywood underlayment screwed every 6″/4″ to…
    – 3/4 plywood subfloor
    The plan:
    – Porcelain 12X24 tile over…
    – Laticrete 317 over…
    – Ditra over…
    – NuHeat heating cables, encased in either thinset or SLC
    Here are my questions:
    1) The entire floor is about 3/4″ in 20 feet out of level. If I use a minimum of SLC, will it result in flat or will it actually try to make the entire floor level (which I don’t really want)
    2) It seems like most of the SLC instructions include the use of metal diamond (or synthetic) lath. I don’t want the increased height and I especially don’t want to risk damaging the heating wires. Is lath really necessary in 3/16″ SLC under Ditra?
    3) If I instead use a thinset and flatten / cure before normal Ditra install, will my dog burst into flames?

    • Roger

      Hey Jim,

      1. It will make it level. It, uhhh, self levels. :D
      2. If you use the primer the lath is normally not necessary in my experience.
      3. You can not build thinset up to 3/4″, so if you’re going that high yes, your dog is likely to combust. :D If you just want to make it flat (you said 3/4″ out of level, not out of flat) then you should be able to compensate for smaller areas as you install the tile.

  • Marge Shuger

    Hi Roger, Did you put tape over your backerboard seams before you installed your wires?
    Thanks for your great information! You helped me out when my son’s bath floor was being installed incorrectly. It’s holding up well.

    • Roger

      Hey Marge, nice to see you again! :D

      Yes, I actually tape and mud the seams as I’m doing the wires. I’m bassackwards like that. But they are taped and mudded.

  • Scott

    Is there really a need for the backer board? I think I read here where if you are just laying tile, I could use Ditra as my substrate over my plywood subfloor. If that is the case, what is the need for the backer board then heating wire then ditra? So the question is, can I just put the heating element on my plywood subfloor, then proceed as you have described laying the Ditra over it?

    • Roger

      Hey Scott,

      Nope, no need in most installations. That particular installation had structural movement issues in the joist system of the second floor. Installing the backer over a layer of flexible thinset gave me an extra layer of uncoupling ability in the substrate. I wanted that layer to deal with the expansion and contraction of the floor system beneath it and the ditra to handle the movement created by the heating element.

      Every installation is different. That is simply the installation I chose photos from because I had more and they were more detailed than others – you don’t need the backer, it can go right over the plywood with ditra.

      • Scott

        Thanks! Your site makes my head hurt. So much knowledge, so little storage room.

  • Neil Brooker

    Hey Roger, Thanks for all your info I was wodering when you call for a 11/8″-1 1/4″ substraight does this include the hardy board? I am doing a 4 by 8 bathroom with the heated floor my floor base is 3/4 shiplap then I was going to put the 1/2″ hardy board on top of that. good, or no good. thx again Neil

    • Roger

      Hey Neil,

      You need a minimum of 1 1/8″ double-layer of ply beneath your tile substrate (the backer). With the 3/4″ shiplap you’ll need a 1/2″ layer of ply over it before your hardi. You can, however, use 1/4″ hardi on your floor rather than the 1/2″.

  • Aaron

    I was just wondering if the tile comes out weird since this system uses no “grid” to keep all the tiles the same level? doesn’t it leave a lumpy, bumpy floor? How do you get around that? Build the floor up after wire down with mortar? Thanks!


    • Roger

      Hey Aaron,

      Yes, if you just slam tile on it willy-nilly it will come out all uneven. If you read part two here: Installing Suntouch Part 2 it will show you how I compensate for that.

  • Rhett


    I have a quick question about this – I am about 90% sure of the answer but wanted to make sure I have things under control. I have several rooms of “Schluter,” experience under my belt, so I am not concerned about that facet of the project. I am concerned about applying the Schluter directly over the top of the warming wires.

    Does the Schluter DITRA become “Bumpy,” when placing it on top of the rows of wire “Clips” that secure the wire to the floor and ensure their spacing? It seems as though you might be asking for a little “ridge” on the floor where these items are installed.


    • Roger

      Hey Rhett,

      Yes it does. You need to either use SLC to flatten your floor before ditra installation or use a larger trowel (higher than the clips or wires) to install the ditra, let it cure, then install your tile.

  • Brian


    Dude, your website rocks. Suntouch should be paying you for hits to this place. Great resource!

    Question for you: So, the new Suntouch product has been rated for shower installation. If I had to guess, after the pan is built, you basically follow your instructions for installing the wire and then the ditra membrane, and then the tile. Do you have any recommendations for this installation? Maybe this is your next article?


    • Roger

      Hey Brian,

      If you are using suntouch in the shower it needs to be embedded into the top mud deck. I cut a large spiral groove in the top mud deck after it cures, insert the wire then skim over it with thinset.

      You do not use ditra in the shower. If you are using a topical membrane such as kerdi or redgard just install it as you normally would over the top. If you are simply using a traditional method in your shower you would simply install the tile right over the top of the mud deck and embedded wire. *You need to wait at leas three days before turning on the heat once it is embedded! That article is on my list – it’s a long friggin’ list and I’m currently running around putting out flaming dogs and corralling midgets (don’t ask) OH! and that whole ‘work’ thing. :D

  • Robyn

    Hey Elf Man
    We are completely remodeling our downstairs bathroom (walkout basement, so you gussed it we are below grade) in North West Washington. So yes, it is a very wet enviroment.
    We are on old cement slab that is not level but is realitively flat. We are installing sun touch heat and are confused about the layering of materials!
    We are planning to start with a product called easy matt( we are using this as a thermal break and vapor barrier) which has an adhesive backing to adhere to the clean! concrete slab( our slab has some small hairline cracks)
    Next the suntouch matt.
    Next a layer of thinset
    Put down the Ditra matt , followed by thinset and tile with Spectra lock Grout.

    Is this right! ok so maybe right enough???

    • Roger

      Hey Robyn,

      Your order of installation is correct. Rather than the layer of thinset only between your suntouch and the ditra you may want to consider putting down the suntouch mat then using a self-leveling cement over it. After that cures then install your ditra with thinset directly to the cured SLC. Not really necessary but makes it much, much easier to create a flat ditra substrate for your tile. But! you can install ditra directly over the suntouch with thinset only so long as your diligent about keeping the ditra flat.