Installing Radiant Floor Heating

1. layout the mat
2. spread thin-set mortar
3. lay tile
4. connect thermostat

1 Lay out the ThermoTile® mats on the room's sub floor.

Its flat, ultra-thin electric cable is factory-mounted on a heavy duty fiberglass mesh designed to lay flat for quick installation. Each ThermoTile® mat has 10' lead wires coming from one end of the mat which needs to be connected to the thermostat. So whether the underfloor heating mat is 5' or 120' long, there is no need to worry about where the mat ends. Follow a layout plan and start the mat so the lead wire reaches the thermostat location.

a. Space heating mats 3" from walls, fixtures and 4-6" from toilet rings. Depending on subfloor type: plywood, backer board or cement slab, adhere the heating mat mesh to the subfloor with staples, tape or hot glue. Be careful not to staple the heating wire.

b. Cut mesh to turn mat.
Do NOT cut heating wire

You can easily cut & turn the mesh to fit the floor space or to go around obstacles. Be careful not to cut the floor warming wire.

c. Turn mats according to your layout plan.

The mesh can be cut in various ways according to your layout plan to fit the shape of the floor being heated. The example at right is a U-turn. See Turning Floor Heating Mats for more turn examples.

d. Pull lead wire(s) & sensor upconduit.

Pull lead wires up conduit to the electrical box for connecting to the thermostat. Connections to the thermostat will be made later. (It is recommended to connect the heating mat lead wires to InstAlarm to monitor the installation and sound an alarm if an accident damages the heating mat.) Pull the thermostat sensor wire up a separate conduit or attach it to the stud.

e. Install sensor probe between heating wires

Before applying thin-set mortar over the radiant heating mats, be sure to place the thermostat's floor sensor evenly spaced between two heating wires. Groove the subfloor a little if necessary to nest the sensor probe so that the floor will lay flat. Weave the sensor through the heating mat mesh to insure it stays in place.

If spreading thin-set mortar directly over the heating mats in one step, we recommend using a plastic trowel to prevent cutting the heating wires.

Or, you can use the flat side of the trowel, and float a skim coat of thin-set that just covers the heating wire, then lay tile in a second step.

Or, you can pour a layer of self-leveling cement, let dry, then lay tile, laminate, carpet, linoleum or other types of floating and glued down floors.

Almost all tile installers use (and we recommend using) polymer
(latex or acrylic) modified Portland cement mortar to lay the tile
and a polymer modified grout. These materials provide flexibility
and prevent grout cracks.

4 Make electrical connections.

Connect all wires to the appropriate terminals on the thermostat. If installing more than one mat, connect each mat in parallel to the thermostat. Although simple to do, an electrician is required by the NEC and UL.

• Line - power from the service panel to the thermostat.
• Load - power from the thermostat to the heating mats.
• Temperature Sensor - connect the floor sensor to the terminals marked "Sensor."