DIY Network

How to Install a Radiant Heat Subfloor

Use these step-by-step instructions to install a radiant heat subfloor that's a great heat source for any room of the house.

More in Electrical

  • Time

    Two Days

  • Price Range

    $2,500 - $5,000

  • Difficulty



Step 1: Set the First Panel

Measure and make a reference line for the first panel (Image 1). Apply construction adhesive directly to the existing subfloor, then set the first panel in place (Image 2). Be sure to follow the plan provided by the manufacturer.

Secure the panel to the joists with 3" framing nails.

Step 2: Stagger the Joints

The channels in the subfloor must line up perfectly (Image 1), so use the alignment tool and a hammer to adjust the panels.

When installing a subfloor, you want to stagger the joints. Cut a panel in half with a circular saw (Image 2). A handsaw can be used to make any small cuts.

Step 3: Notch Out the Channel

Some panels will need to be tied together to accept the tubing. Line up the jig on the adjacent channels and temporarily secure it with screws (Image 1). Use a plunge router to notch out the channel (Image 2).

Deburr the channel with an angle grinder. Any metal shards could damage the tubing.

Step 4: Make a Hole for the Tubing

Drill into the subfloor to make a hole for the tubing to run into the basement. Use a unibit to go through the metal, then follow up with a forstner bit to go through the plywood.

drill into subfloor to make hole for tubing

Step 5: Run the Tubing

Run the tubing down to the boiler leaving about 5' of slack (Image 1). Following the plan from the manufacturer, run the tubing in the channels and press it down with a 100 pound roller (Image 2).



  • Subfloor from Warmboard
    Casement windows, awning window and French door from Pella
    Red Oak floor from Maxwell Hardwood Flooring