Over the last couple of years, radiant floor heating systems for tile and stone floors have become one of the most desired applications amongst homeowners. Whether for a small area of a living space or throughout an entire home, there are plenty of options available and a variety of different systems on the market. And for those who have had the pleasure of walking on a heated tile floor, it’s likely that they won’t ever want to revert to a floor without it — especially in regions that experience harsh winter temperatures.

This was the case for one couple located on the North Shore of Massachusetts in the city of Beverly — a place that frequently experiences brisk temperatures and is no stranger to unforgiving winters. They wanted to ensure they never stepped on a cold tile again while walking around on their kitchen floor. To accomplish this, the couple decided to hire a local tile installer, Salvatore DiBlasi, owner of Elite-Tile Co. in State, MA, to install the Prodeso Heat Membrane System by Progress Profiles using the SunTouch® WarmWire heat cables. DiBlasi, who has 30 years of experience in the tile industry, has installed numerous electrical floor heating systems. However, this was the first project he worked on utilizing the Prodeso system, which he explained can’t be installed under any appliances such as dishwashers, refrigerators or stoves; has to stay at least 3 inches away from walls and between 1 to 2 inches away from any toe kicks; and can’t be put in closets because the wires need to be exposed.

To demonstrate how to properly install the Prodeso Heat System, DiBlasi documented his entire installation of the residential kitchen — from start to finish — via a YouTube video. The step-by-step video details each step of the installation process — from how to cut the Prodeso Heat Membrane sheets to size to how to test the final product to ensure it works correctly. DiBlasi frequently uses YouTube to record his other tile installations to show other installers how to properly utilize certain products and lend advice, if and when needed.

As DiBlasi demonstrates in the video, the first step to installing the Prodeso Heat Membrane System is properly cutting the Prodeso Heat Membrane sheets to fit whatever sized space you’re working with, which in this case was a kitchen floor that measures 140 square feet. The membrane sheet, which is blue in color, is a polypropylene uncoupling crack isolation waterproofing membrane with rounded square-shaped reliefs that are only 1/4 inch thick (5 mm). The sheets need to be cut to fit the floor, but also need to be cut so that the square-shaped reliefs line up with each other, side by side, so that the heating wires will be able to lie next to each other once the sheets are all laid down.

After all of the membrane sheets were lined up and laid down, DiBlasi began his prepping process. “Before laying the thinset, I dampen the floor with water to remove any dust and give the plywood a little ‘drink’ so it doesn’t suck the moisture out of the thinset, which can dry prematurely sometimes,” he explains in the video. “The water allows the thinset to cure better. Then, I always use the flat trowel first, which keys the thinset into the substrate, then I flip it over and use the notched side. I usually use a wooden trowel to flatten it out and get all of the air bubbles out and push it into the thinset so you get really good coverage and adhesion. Prodeso Heat recommends using a 3/8-inch x 1/4-inch trowel to install the membrane to the substrate (plywood, concrete or whatever you’re installing to).”

To install the mat on the plywood subfloor, DiBlasi used Mapei’s Ultraflex 2 white modified thinset. After the thinset was laid, he then laid down the Prodeso Heat Membrane sheets, used the wood trowel to secure them and remove all of the air pockets, and repeated that until all of the sheets were laid down across the entire kitchen floor.

Installing the heat cables

After the Prodeso Heat Membrane sheets were securely installed to the plywood floor, DiBlasi began the second part of the system’s installation — the WarmWire® floor heat cables from SunTouch, which are placed atop of the membrane sheets in between each of the square-shaped reliefs. The WarmWire cables come in two different voltages — 120 and 240 volts — which are chosen based on the square footage, amount of heating needed for the space and the type of voltage available. The 140-square-foot kitchen had 240 volts available.

DiBlasi explained that the most important thing about the wires is that they need to be tested three times — once when they’re taken out of the box, once when they’ve been installed in the Prodeso Heat Membrane sheets, and lastly, when the tile has been installed over the sheets to ensure they’re working properly throughout the entire installation. Each of the tests need to be logged in the SunTouch installation manual to record the testing values as well, which DiBlasi demonstrates in the video.

To install the WarmWire heating cables, DiBlasi uses a rubber float to press them in between the square pegs on the Prodeso Heat Membrane sheets. “You don’t want to use anything sharp that can damage the wires like a steel trowel,” DiBlasi explains in the video while installing the cables. “The wire can go either every two or three pegs wide, or an alternating combination, so there’s constant even heat — and so you don’t get any hotspots.” Installers can also use their hands to lay the wire, if they don’t have a rubber float available.

Since the WarmWire cables can’t be cut or modified in any way — shortened, lengthened, etc. — the installer needs to order the correct length for the area being covered. The wires can also never be crossed or overlapped, according to DiBlasi. “They’re always going to be in separate channels,” he said. “They’re never going to overlap or cross each other.”

After the WarmWire cables were installed, DiBlasi cut two holes in the middle of the Prodeso sheets for the two probes, which are made to be connected from the sheet to the thermostat in the wall. The probes are essentially the wires that get the system up and running, which can’t be connected to the thermostat by just a regular installer, as noted by DiBlasi. Although this would complete the installation, DiBlasi left the probes to be installed, as he noted that they should be installed by a licensed electrician and not the installer. “The installer should just connect the probes to the mat and snake the wire to the wall and leave it there for the licensed electrician to complete,” explained DiBlasi.

Once all of the wires and probes were secured, DiBlasi embarked on the last step of the installation — laying the 12- x 12-inch porcelain tiles atop of the newly installed heating system. DiBlasi used Tec’s Uncoupling Membrane Mortar, an unmodified thinset, on top of the Prodeso sheets to prepare the surface to lay the tile. He explained how he used a 3/8- x 1/4-inch trowel, but also said that it depends on what size tile you’re laying as to what sized trowel you should use to lay your thinset. “If you’re using a larger tile, I suggest using a larger trowel,” said DiBlasi. “I also always back butter the tiles before I set them because you get much better coverage on the back of the tiles — usually 100%. And that’s the goal: to get as good of coverage on the back of the tile as possible.”

Once DiBlasi applied the thinset and filled in all of the spaces between the square-shaped nobs of the Prodeso Heat Membrane sheet, he flipped the trowel over and notched out the thinset. “This gauges the thinset so you get an even bed of mortar, and it keeps all of the trowel lines in the same direction so it’s easier to collapse the lines as you push the tile in and get 100% coverage on the back of the tile,” explained DiBlasi.

DiBlasi then laid down the tile, pushing it back and forth to make sure it was firmly secured. “Because the floor is being heated, there’s going to be a lot more expansion and contraction of the floor, so be sure to leave enough room for that at the walls and anywhere that the tile is on floor,” he said. “Use caulk where tile meets hard surfaces — like around steps and outside doors.”

The installer explained that he did run into one minor challenge on the jobsite, which slightly extended the time it took to finish the five-day job. “Usually, it would take about four days to do something like this, but because of the limited access I had, it took a little longer — about a day longer than usual,” said DiBlasi. “I couldn’t put my tools or wet saw in any other room in the house or in the garage, and it was freezing cold outside at the time, so I had to put them in the same room as where I was working.”

However, despite the one minor roadblock DiBlasi encountered, overall he said the installation ran smoothly and the homeowners are happy with their newly heated kitchen floor, which is no longer cold when any of the family members step foot on it.

“If you put your hand on a tiled floor in the winter, it’s extremely cold,” said DiBlasi. “This system eliminates that problem. It just makes it more comfortable. If you go on a heated tile floor and go off of it, you would never want an unheated tile floor. It just makes it so much nicer.”

Installation Details

Residential kitchen

Beverly, MA

Tile Installer: Elite-Tile Co., State, MA

General Contractor: Testa Building & Remodeling, North Andover, MA

Installation Products: Prodeso Heat System from Progress Profiles of Randolph, NJ; WarmWire® floor heat cables from SunTouch (a Watts Water Technologies company) of Springfield, MO; Mapei UltraFlex 2 of Deerfield Beach, FL; Tec Uncoupling Membrane Mortar of Aurora, IL

Number of Installers: 1

Installation Time: 5 days