Manual

16 SunTouch WarmWire Installation Manual
Mortar bed
Insulation
(per International Residential
Code, Chapter 11)
Latex-Portland cement
mortar bond coat
Heating cable
Backer board
Plywood subfloor
Tile/stone
FRAMED FLOOR
Construction and Applications
Thin-set mortar over framed floor
(Dry-set or latex cement mortar; TCA #RH130-03)
Thick-set cement mortar with lath
(Cement mortar metal lath; TCA #145-03)
Thin-set mortar over framed floor
(Dry-set or latex cement mortar; TCA #F144-03)
Joist
Insulation
(per International Residential
Code, Chapter 11)
Latex-Portland cement
mortar bond coat
Heating cable
Plywood
Plywood subfloor
Tile/stone
Joist
Insulation
(per International Residential
Code, Chapter 11)
Latex-Portland cement
mortar bond coat
Heating cable
Metal or plastic lath
Plywood subfloor
Tile/stone
Mortar bed
Joist
be sufficient for most regions, while
in more temperate areas R-11 will
suffice.
Do not install rigid insulation lay-
ers direc tly above or below backer
board or mortar. If possible, install
insulation as shown in the diagrams
at right.
Reinforcement. There are several
options for strengthening the sub-
floor:
1. Add 3/4”-thick plywood on top
of the existing subfloor.
2. Pour a 1/4”–1/2”-thick layer of
self-leveling mortar over the existing
subfloor, then install the cables on
top of the mortar layer.
3. Install a quality cementitious
backer b oard or fiber cement under-
layment over the subfloor. Then install
the cable and lay the tile.
Antifracture membrane. While
optional, it is recommended that an
antifracture membrane be installed
to reduce the chance of minor stress
and frac turing in the subflooring
from being transmitted upward to
the tile. If an antifracture membrane
is used, install the cable above the
membrane, unless otherwise recom-
mended by the membrane manufac-
turer.
In place of an antifracture mem-
brane, an uncoupling system can
be installed to prevent deflection in
the subfloor from affecting the tile
surface.
Mortar Beds
The cables can be installed in
three types of mortar beds: thin-set or
thick-set mortar beds 3/8” to 1” thick,
and self-leveling mortar b eds 1/4” to
1/2” thick.
Thin-set Mortar Beds. If the cable
will be placed directly onto the slab,
or if backer board or plywood rein-
forcement is used on a plywood sub-
floor, first install the cable then apply
the thin-set mortar bond coat directly
over the cable and lay the tile.
Thick-set Mortar Beds. If a thick-
er mortar bed is used to strengthen
the floor, the cable can be installed
under either the mortar bed (also
known as “dry-set”) or under the mor-
tar bond coat directly below the tile
or stone. In a thick-set applic ation, the
cable is generally installed above the
mortar bed, but before the thin-set
bond coat. Thick mortar beds of this
type require the use of a reinforcing
mesh or lath.