Heated flooring systems are a phenomenal option for bathrooms. They heat up the floor tile and make the space way more comfortable. Here is an overview of installing the DITRA-HEAT Heated Flooring Systems. Ever since DITRA-HEAT came out on the market, it has transformed the amount of time it takes to install heated floors. It takes out a lot of the extensive planning. Often when you’re building a bathroom, you end up moving a vanity or making other layout changes. Older floor heating systems often required you to send out a schematic and have a mat built for the room, which takes time—it could take up to 2 to 3 weeks to get something like that in.
Other systems require floor leveling. You put all the cables down; then you have to level everything. That can be problematic for many reasons. Some areas may not fill correctly, and it can be a difficult thing to make sure that some of the loose wires actually stay intact on the floor. With DITRA-HEAT, the components are a heated mat system. You order the cable to fit your dimensions.
There’s a great calculator on schluter.com that will give you directions on how to figure out the square footage of what you want to install for heating. You don’t have to do all the bathroom: if you have an area that doesn’t need floor heat, why spend the money to do it? The site has a great way to calculate what you need. Another great thing about this system is that the whole floor is waterproof, so there aren’t additional steps to waterproof the system, which is perfect because a lot of showers and things that are being built now are curbless.
You want to keep an expansion joint between the wall and the DITRA anywhere between 1/8” to ¼”. For a longer room, you can lay out half, thinsetting it down, rolling the other half up, and thinsetting that down. It makes it a little bit easier, and you’re not walking in thinset to put it down. For the DITRA-HEAT you want to use a ¼” x ¼” square notch trowel. Just like any other tile installation, you want to wipe any dust off with a damp sponge. This also helps keep the plywood from sucking the moisture out of the thinset right away. It’s always good to pull back the DITRA-HEAT and make sure that you have 100% coverage on that.
If your wall isn’t 100% straight, you can just take a utility knife and score it down along the wall just to get that extension joint there. You just have to make sure that the studs are in line with one another because that’s how the wire’s going to be run through this. You can make as many pieces as you really want out of the DITRA-HEAT mat—so whatever is the easiest way to get that done.
We can’t emphasize enough how important it is to burn the thinset into the wood subfloor; it’s absolutely necessary. You also want to have directional troweling so that all the trowel ridges face the same direction. When you embed the DITRA-HEAT membrane, you’re going to collapse the ridges. Again, you also want to make sure the studs are somewhat in line with each other.
If there’s an area that you don’t want heat, still buy enough DITRA-HEAT mat to do the whole thing, and just run the wires where you want to. You can run the DITRA mat over the the toilet flange and just and cut nicely around the flange.
You’re going to run through a few basic tests that you need to do to check to make sure that your cable is good: when you take it out of the box, that it’s good after you install it into the floor, and that it’s good after you have the tile on. A lot of this pertains to your warranty. Go on the website; research the warranties. The silver card is important: it has your serial number on there. The first thing to do is test the resistance on this cable to make sure it matches the value written on the tag. Test number two is going to be testing the heating cables to the ground wire. The third test checks whether or not there is anything in this cable that is close to shorting.
That completes the testing of the heating cable itself. Then you’ll test the thermostat wires. Make sure that when you’re done getting all the numbers, you write it down on the warranty sheet that comes with your DITRA-HEAT. This is really important for the purpose of the warranty.
Once everything is tested and the mat is in place, there’s a couple of rules of thumb with running the wires. One of them is wherever your cabinetry is, you don’t want to be running that wire underneath the cabinet. You want to be 3” away from every wall. You want to be 6” to 8” away from any toilet flange or any type of drain. And then you want to be 8” away from any heating source, especially if you have an in-floor heated source like a vent in the floor.
If you’re using a floating sink or a free-standing sink where there’s no toe-kick, you can run wire underneath there. For the cabinets, you don’t want to be trapping heat underneath, so avoid putting any wires in that area.
Take the wire and wrap it all the way to the other side of the room, then work your way back. You can’t space them any closer than 3” apart. You can hear how all that just snaps in so this wire is nice and flush with the top of the DITRA mat, and it’s easy to work with it. Now you could use a grout float to make things a little bit easier. Most bathrooms are not going to have an issue with it, but if you had a very large room that was more than 10 ft long, you don’t want to run the wires continuously straight for more than 10 ft. If you’re going over 10 ft in length, just do a little jog and then continue.
The beauty of this is that you can just make this wire fit any dimension that you want. It makes it a lot easier and less planning when you can just be able to wrap the wires. So this really kind of makes it fool-proof. It’s very quick. There will be two floor sensors: one in the package with the wire, and one with your thermostat. You want to run both sensors in the floor in separate locations.
If anything ever happens with one of the floor sensors, you can hook up the other one. So you want to make sure that they’re on opposite sides of the room or pretty far from each other. There’s no sense in putting them in the same area. You want to have them in between two wires. You don’t want to have it closer to one wire and not the other. So the best way is to just basically just cut the DITRA stud and then just slide the sensor in at a diagonal. Then you’ll have the same spacing in between each wire. And then since this wire is so thin, it doesn’t exactly stay in; it doesn’t snap in place like the DITRA wire does.
Three quick tips about the DITRA-HEAT sensor:
Number one: if you have a skylight in your bathroom or in a space where you’re going to be putting the DITRA-HEAT, make sure that that sensor isn’t in place where a lot of light comes down through the roof because that will heat up the sensor and give it a false reading, and the DITRA-HEAT won’t kick on.
Number two: if you have an animal, for example a dog or a cat, and they have a favorite place in the room where you’re putting the DITRA-HEAT—let’s say that the dog likes to kind of sit next to the bathtub—don’t put the sensor there, because the sensor will pick up the heat from the dog and won’t allow the DITRA-HEAT to kick on.
Number three: don’t put the sensor directly in front of a vent, where hot air’s going to blow onto the sensor, and again, that’s going to provide a false reading to the thermostat in the bathroom.
Next you’ll do another set of tests, making sure that all of the circuits are good, following manufacturer instructions. Again, this is important for your warranty. Follow the instructions for hooking up the thermostat, and you’ll be ready to complete your flooring installation. Soon you’ll be enjoying a comfortable heated floor in your new bathroom.