I have an attic conversion project that i am bidding and they are looking to use either open or closed cell spray foam insulation for the ceiling.
Foam insulation around can lights.
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.
2x8 construction with osb roof sheathing.
Recessed can lights and spray foam in attic right now with the ic cans i plan to wrap them with fiberglass batting.
Stuff the insulation around the gap between the lip of the can and the drywall.
Apply the sealant around the cable and along the edge of the cover where it rests on the ceiling.
Even though i already air sealed all my light fixtures from within the attic i decided to go above and beyond by air sealing the very same fixtures.
I think it will be best to keep an airspace between the batting and the can so i will make some sort of wire cage to do this.
Notice that i said regular insulation such as fiberglass or cellulose insulation not spray foam insulation.
Now it will be safe to heap insulation onto that spot.
The plan is 6 7 of spray foam.
4 construct a circular dam to place around each can with wire mesh or sheet metal if the lights are not ic rated.
Spray foam insulation is an air seal and works a lot better than regular insulation does.