Construction Methods
for Radiant Floor Heating Systems
New Construction Applications
Slab*
When placing a Radiant Floor Heating System in the concrete slab the area needs to be brought to
grade (make sure it is smooth and level). Vapor barrier and sand, are optional. Continue with
2" of ridged board insulation (use; Owen Corning- pink or Dow- gray or blue) which give you
an R-value of 10. Tubing is then stapled directly to the insulation with foam staples, complete by
covering tubing with 3.5" - 4" of concrete.
Recommendation: When working with a Radiant Floor Heating System in a concrete pour;
plywood should be placed down to wheel concrete over. This is done as a safety measure; in the
event the front of the wheelbarrow is accidentally dropped having dried, sharp concrete on the
front of it. Dropping the front could pierce the tubing.
Suspended Floor*
A Radiant Floor Heating System placed on a suspended floor; the tubing is merely stapled or nailed
(with tube talons) to the sub-floor. A lightweight gypsum pour at 1.5" thickness is poured
directly over the tubing. In new construction all suspended floor areas should have an added sill
plate. A 2 x 8 sill would be added to 2 x 6 construction. The 1.5" sill ledge which is created
by the added sill is to allow for the 1.5" gypsum pour. Also, ensures problem free framing for
doors and windows and also leaves a tack plate should carpeting be the floor covering.
Recommendation: When placing a Radiant Floor Heating System on a suspended floor, the joist
cavity below MUST be fully insulated. Use either R-19 batte or 2" ridged.
Retro-fit Applications
Joist Heating**
A radiant floor heating system placed in the joist cavity will have the tubing spaced 8" on
center. The tubing is left hanging 2" below the sub-floor and is supported every 3'-4' by
tying the tubing to metal joist hangars (basset brackets) with wire twist ties.
Allowing the tubing to hang freely enables the cavity to fill up with warm air and radiate the
warmth evenly across the floor above.
Insulation must be placed below the tubing to drive the heat upward. Insulate with either R-19
batte or 2" ridged insulation.
Suspended Floor
A radiant floor heating system placed on an existing suspended floor; the tubing may be applied
in a few ways.
- Over Pour System* - The tubing is merely stapled or nailed (with tube talons) to the
sub-floor. A lightweight gypsum pour at 1.5" thickness is poured directly over the tubing
followed by the floor covering, or 1" dry tamp mud set followed with ceramic tile or the like.
- Aluminum Plate Method** - 1 x 6 firing strips are nailed onto existing sub-floor. Tubing
is snapped into aluminum plates. Place new sub-floor on top following with floor covering.
- Quik Trak™ System** - Place the "Quik Trak" system (5/16" tubing)
onto existing sub-floor or concrete. Tubing is then snapped into system. Floor covering may be
placed directly on top of system.
*Space heating: A Radiant Floor Heating System applied in these methods will
give you 100% space heating.
**Floor warming: A Radiant Floor Heating System applied in these methods will
provide floor warming ONLY. These methods do not provide required btu's of energy to supply the area
with 100% complete space heat 100% of the time during the heating season. Supplemental heating will
be required in most cases with these application.
