How to Insulate an Attic Floor Around Lights

Inspect your ceiling mounted light fixtures to see if they are able to contact insulation. If they are not, installing insulation directly on, or around them, may be a fire hazard. If they are IC or Insulation Contact rated, you may place insulation directly over them.

Use your tape measure to record the distance between the two floor joists on either side of your recessed light fixture. Use your circular saw to cut 1-by-6 inch lumber to bridge the gap between the two joists. Install one length on either side of the light fixture, so that a box is formed around it.

Inject spray foam insulation into any gaps around the edges of your lighting fixture and into any wiring holes which may exist. Allow the insulation to dry according to the manufacturer's instructions.

Cut a piece of fiberglass insulation to fit the box in which your light fixture sits. Place the insulation inside a plastic garbage bag so that it lays flat. Place the insulation bag over the fixture, with the backing side facing downward, so it fits snugly into the wooden box you have created. The plastic bag will add a waterproof barrier to the insulation. If your fixtures are not IC rated, cut and fit insulation to fill the spaces around your light, but do not install any insulation closer than three inches away from the fixture itself.