In the first section of our how-to guide, you learned how to measure for the underfloor heating mat installation, test the heating mats and prepare the subfloor. Now it's time to learn how plan the layout of the mats and how to prepare for the thermostat installation. So, let's get started.
Step 1 - Choose Location for Thermostat
Before you can start installing the heating mats, you'll need to choose the location for the thermostat. Choose a location that is approximately 4 to 5 feet up from the floor and is conveniently situated. You may choose to install the thermostat close to a light switch or on another wall. Make sure that it is not on the wall that may frequently be splashed with water.
Step 2 - Dry Layout of Mat
Before you affix the heating mat to the floor, you should first do a dry lay out of the mat. When laying out the mat, mark positions for cuts or turns with your permanent marker. Start by laying the power cable closest to the area you have chosen for your thermostat. If you are installing more than one heater, make sure that all power leads can reach that thermostat before you affix or cut the heating mats. Also, when planning your layout, be sure that all element wires are at least 3/4 inch away from each other and that they never cross.
Step 3 - Cut and Affix the Heating Mat
After you have marked the floor and are sure the layout is planned correctly, you can begin cutting and turning the heating mat. When cutting the mat, cut the mesh only and never the wire. You can cut as much of the mesh away as needed. If you cut the mesh away from the wire, space loose heating wires at least 2 to 3 inches apart and make sure the wiring never crosses. Use the double-sided tape included with the mat (or masking tape) to make sure the mat is securely affixed to the subfloor and also tape any loose wiring. Check edges and corners to make sure they won't be damaged or snagged during tiling.
Step 4 - One Last Test with the Multimeter
Perform a final test of the heating wire with the multimeter to insure that the mats were not damaged during installation.
Step 5 - Layout and Test Floor Sensor
Some underfloor heating mat kits come with a floor sensor that is used to gauge the actual temperature of the floor area (instead of only the temperature of the room). If your kit comes with one of these sensors, lay it under a section of the heating mat and tape it securely. Make sure the wire for the sensor can be bundled together with the heating wires.
Step 6 - Run Wire to Planned Thermostat Location
Measure and cut the wire cover molding so that it will reach the location for the thermostat. Then bundle the heating wires (and floor sensor wire if applicable) and place them inside the molding. Snap the cover of the molding closed. Remove the seal from the double-sided tape on the rear of the molding and press the molding into place on the wall. The heating wire should now be protruding out of the top of the molding.