how to extreme

Install a Heated Wood Floor

Construction How-To, Flooring Installation, Floors, Radiant Heat August 9, 2016 Sonia


Nail the sleepers throughout their length, using two nails at each end.

Nail the sleepers throughout their length, using two nails at each end.

The sleepers were spaced 16" on-center, which creates a 10" wide space between them to run three loops of radiant cable spaced 3" apart.

The sleepers were spaced 16″ on-center, which creates a 10″ wide space between them to run three loops of radiant cable spaced 3″ apart.

Best Practices: Installing the Warmup Radiant Heat Cables

Several flooring manufacturers have tested their products specifically with Warmup products and certified their warranties on combined installations. This list includes Amorim, Wicanders, and Higuera Hardwoods, among others.

The Warmup kit includes all components needed for its Loose Cable Underfloor Heating.

The Warmup kit includes all components needed for its Loose Cable Underfloor Heating.

Installation Tips:

  • Use 1/4-in. or 3/8-in. sleepers so that filling the voids with leveler will give you an effective heat bank, yet only minimally raise floors.
  • Using the standard 10-in. spacing for 3-in. wide sleeper runs, we spaced three runs of cable (spaced at 2”, 5” and 8”) in each sleeper gap.
First step is installation of Warmup's fixing strips.

First step is installation of Warmup’s fixing strips.

Note: Depending on your specific conditions, you may need to adjust sleeper spacing to accommodate the support of the wood floor.

  • For installations over concrete and/or requiring insulation, a variant of the sleeper method is to use 2×3’s or 2×4’s partly embedded in the slab pour. This allows for insulation to be included and more thermal mass to be poured between the sleepers. Warmup’s regular NADWS floor heating or WODH slab heating cables can be used in these applications.
Lace the heating cable on the fixing strip.

Lace the heating cable on the fixing strip.

Encapsulating the Radiant Heat Wires

Once the cables are in, pour concrete between the sleepers. This creates a thin radiant slab that encases the cables. In all cases, a layer of insulation is normally placed below the existing subfloor to ensure that most of the heat is directed upward.

Run the heating cable back and forth in parallel to the wood sleepers until all the sections are filled.

Run the heating cable back and forth in parallel to the wood sleepers until all the sections are filled.

I used latex-modified thinset (LMT), which is a blend of cement, very finely graded sand, and a water-retention compound that allows the cement to properly hydrate. LMT is cheaper than a self-leveling pour, which is frankly not needed in this situation.