Install Instructions

IOM-WR-WW 1616 24 of 36

Never bang a trowel on the Heating Wire to remove excess mortar from the trowel. This

could damage the heating wire.

Mortar Applications with CableStrap:

If a backer board or plywood sheeting is used to strengthen the floor, or if the heating

wire will be placed directly onto the slab, install WarmWire in the thin-set mortar bond

coat above these materials.

If a thicker mortar bed, or self-leveling concrete, is used to strengthen the floor, the

heating wire can be installed in either the mortar bed (dry-set) or in the mortar bond coat

directly below the tile or stone.

The heating wire is generally installed above the self-leveling mortar in a thin-set bond coat.

Use plastic lath instead of the typical metal lath when installing in a self-leveling layer.

Self-leveling mortar with CableStrap:

Self-leveling mortar may be used in CableStrap / WarmWire installations when the finished

surface needs to be smooth. This is applies to engineered wood, vinyl, laminate, or carpet

floor coverings. Attach the WarmWire to CableStrap on the subfloor or slab, then pour

self-leveling mortar 1/4" to 1/2" thick according to manufacturer’s specifications. Install floor

covering after the mortar has fully cured.

Special Precautions

Isolation Membrane: Install the heating wire above the membrane, whenever possible,

unless recommended otherwise by the membrane manufacturer.

Insulation: Insulation dramatically enhances the performance and efficiency of floor-warming

systems. Do not install rigid insulation directly above or below backer board or mortar.

Mosaic Tile: When installing mosaic tile, it is recommended to apply a two-step process.

First, embed the heating wire in a thin self-level mortar bed (1/4"–3/8"), then thin-set the

mosaic tile according to typical practice.

Expansion Joints: Do not install heating wires through an expansion joint. Install heating

wire right up to the joint, if necessary, but not through the joint.

Double-plywood over frame floor

Insulation

(per International Residential

Code, Chapter 11)

Latex-Portland cement

mortar bond coat

Heating cable

Plywood

Plywood subfloor

Tile/stone or laminate flooring

Joist