How to Install Radiant Heat Under a Solid-Wood Floor
With General Gontractor Tom Silva, This Old House television
Approximately 2-4 days for an average-size room
About $10-$15 per square foot, plus mechanical component costs
Difficulty: Hard
About This Video
Steps: 1 Fasten the heat transfer plates to the underside of the old floor with ½-inch screws. Install two parallel rows of plates between each pair of floor joists. 2 Snap the flexible PEX tubing into the grooves of the heat transfer plates. When necessary, bore ⅝-inch holes through the joists to continue the run of tubing. 3 Cover the tubing and transfer plates with aluminum foil. 4 Spray open-cell foam insulation between the floor joists, covering the foil and insulating the tubing. 5 Use a ⅛-inch notched trowel to spread flooring mastic onto the old hardwood floor. Work in small sections to prevent the mastic from drying out. 6 Set the new hardwood flooring down into the mastic, then fasten it with an 18-gauge pneumatic nailer filled with 1-inch nails. 7 Use a hammer and chisel to pry the floorboards tight together prior to shooting in the nails. 8 Fill the nail holes, if desired, with wood putty, then sand the floor smooth. 9 Apply at least three coats of polyurethane to the new floor.
Shopping & Tool Lists
Supplies You Will Need:
1. ⅜-inch-thick hardwood flooring used to cover the old floor 2. Urethane flooring mastic used to adhere the new hardwood floor to the old floor 3. Heat transfer plate used to hold PEX tubing against underside of old floor 4. PEX radiant-heat tubing delivers hot water for heating the floor 5. ½-inch screws for fastening transfer plates to underside of old floor 6. Aluminum foil used to reflect heat upward toward floor 7. Open cell foam for insulating space under transfer plates 8. Polyurethane used to finish the new floor
Tools You Will Need:
1. ⅛-inch notched trowel used to spread the flooring mastic
2. Hammer and chisel used to pry the new floorboards tight together
3. 18-gauge pneumatic nailer with 1-inch nails for fastening down the new hardwood floor
4. Drill with ⅝-inch bit for boring holes in the floor joists for the PEX tubing
5. Wood putty used to fill nail holes in new floor
6. Floor sander, used to smooth the new floor prior to applying a finish