How to Install Radiant Heat With Spray Foam

Double-check that all radiant floor tubing is secured with clips to the bottom of the subfloor and that the system has been pressure tested for leaks.

Measure the length and width of all floor bays --- the area between each floor rafter. Using the utility knife, cut the FSK paper into strips --- the same dimensions as the floor bays.

Install the FSK paper using the staple gun. Simply hold the reflective side up, facing the radiant heating system and the surface to be heated. Place a staple every 12 inches on both sides of the paper to hold in place. Take special care to avoid stapling the tubing. Once completed, you should not be able to see any of the tubing feeding the radiant heating system.

Read the instructions in the spray foam kit along with the included MSDS (Material Safety Data Sheets).

Cover the floor with dropcloths and anything else in the room you cannot remove prior to spray foaming.

Put on the disposable coveralls, gloves, safety glasses and respirator, then turn on the spray foam kit.

Install about 2 inches of spray foam to the entire surface of the FSK paper. Make sure the foam touches each side of the floor joists to make a complete air seal. The idea of installing the foam is to ensure the heat from the system can only reflect up through the subfloor and not heat the space below. The more attention paid to air sealing, the more efficient the system will perform.