Installation Guide

INSCT0816
8
GETTING STARTED
SUBFLOOR PREPARATION
PLYWOOD SUBFLOORING TIPS
Self-leveling mortar
If self-leveling mortar is used to cover the cables, all suboor gaps must be lled to prevent liquid mortar leaks. You must choose waterproof plywood (BC r).
Before buying another type of plywood, you should call your concrete manufacturer.
Surface preparation
Plywood surface must be clean, solid and dry. Remove any dust, oil, grease, paint, wax, sealant or any other substance that could impede adequate adhesion.
Also, the plywood surface must be free of any debris, protruding nails and screw heads, etc. that may damage the heating cable.
Plywood suboor strength and strengthening
Each plywood sheet must be secured with screws spaced 8 inches (203 mm) apart on its center and 6 inches (150 mm) apart on its perimeter. Plywood sheets
must be spaced 1/4 inch (6.3 mm) from each other to allow room for material expansion.
In order to eliminate all risks of damage to the heating cable resulting from oor covering cracks, it is important to ensure sufcient suboor rigidity.
Floor joists spaced 16 inches apart or less require a plywood suboor thickness of at least 1 1⁄4 inch (2 x 5/8 inch sheets). Otherwise, if oor joist spacing exceeds
16 inches, the plywood sheets must be strengthened to achieve a total thickness of 1 7/8 inches (3 X 5/8 inch).
Besides plywood sheeting, there are other methods available for strengthening a suboor such as the use of metal lathes, concrete boards and others. Seek the
advice of a oor covering specialist to make sure that the suboor is properly strengthened.
CONCRETE SUBFLOORING TIPS
Surface preparation
Concrete surface must be clean, solid and dry. Remove any dust, oil, grease, paint, wax, sealant or any other substance that could impede adequate adhesion.
Also, the cement surface must be free of any debris, protruding nails and screw heads, etc. that may damage the heating cable.
Curing period
Before installing the heating cable, the curing period of the concrete must be completed (typically 28 days). If needed, refer to a concrete manufacturer to know
the exact curing period of your type of concrete.
MEMBRANES
Waterproof membranes can be used in bathrooms and/or other locations. They are typically unaffected by the heat produced by the heating cable. However, it
would be safer to check with the membrane manufacturer to see if their product is compatible with the radiant oor heating system and to learn how to install the
membrane properly.
MOUNTING BRACKET INSTALLATION
3 OR 4 INCH (76 OR 102 MM) SPACING USING PLASTIC MOUNTING BRACKETS
The STELPRO mounting brackets enable the easy installation of the cable at 3 inch (76 mm) or 4 inch (102 mm) spacing using their molded hooks.
Plastic mounting brackets: 3 inch spacing for a 12 watts
per square foot density
Plastic mounting brackets: 4 inch spacing for a 9 watts per square foot
density
FIGURE 9 FIGURE 10
FOR PRIMARY HEATING FOR COMFORT HEATING (FLOOR)