If you are creative you can also use spray foam to glue your boxes together.
Seal seams around lights and vents in attic for insulation.
It s easy to overlook electrical wires ducts pipes and vents in the attic but the openings around these are holes can compromise the air sealing of your attic.
To apply insulation measure the circumference of the duct and use a utility knife to cut foil faced fiberglass insulation to the proper size add a couple of inches so the ends can be drawn together easily.
Use a continuous strip of foil tape to seal off all longitudinal seams along the straight runs of the duct.
Now it will be safe to heap insulation onto that spot.
For larger holes filler material may be needed.
Up in the attic clean the ceiling surface around each fixture slit the cover to accommodate the electrical cable and place the cover over the fixture.
How to air seal recessed can lights from the inside.
Cut a 24 inch long piece from a batt of iberglass insulation and place it at the bottom of a 13 gallon plastic garbage bag.
Apply the sealant around the cable and along the edge of the cover where it rests on the ceiling.
You need to leave at least 3 inches on all sides of the light.
Cover the area with insulation again when you re done.
Notch a hole for your wire and spray foam around the bottom and any gaps in the box.
Seal fireplace and furnace holes.
Seal the foil to the frame with the caulk adhesive and staple or nail it in place if needed.
Push back the insulation and scoop it out of the soffits.
Add or remove insulation from the bag as necessary to ensure it fits.
If you have recessed light fixtures in your home you may also have a significant volume of conditioned air escaping into your attic.
Soffits may be filled with insulation or covered with cardboard or fiberglass batts.
Although the insulation is dirty it is still okay to use.
There is no need to remove and replace it.
After sealing the areas just push the insulation back into place.
To seal these openings use caulk or spray foam.
Now plug the open stud spaces photos 1 and 2 and seal the top of the cavities with reflective foil photo 3.
You can seal large stud cavities in your attic around dropped soffits under kneewalls and around recessed lights by stuffing insulation into a garbage bag and then plugging the cavity with it.
You can stem the flow of air and money by air sealing your light fixtures from the inside with just a roll of painter s tape a can of spray foam insulation and a tube of painter s caulk.
Then use a paintbrush to apply duct mastic to the joints where an elbow connects to a duct.
Use expanding foam or caulk to seal the openings around plumbing vent pipes and electrical wires.
Apply a bead of caulk or adhesive around the opening.