Air sealing around can lights. Ideas?

[WillyP]

About vapor barriers. It's been beaten to death for decades now. There is an overwhelming body of empirical evidence showing that when cellulose is used a vapor barrier can actually be hazardous.

I agree. I think when using cellulose it is far better to allow it to dry. But I do have a question. Is there an interior paint that allows moisture to penetrate it, so my insulation can dry better?

[MarkTrestt12]

Insulating paint, or thermal paints, are decorative coatings that are specifically designed to improve the thermal performance of a surface. Insulating paints all function in different ways, depending on the situation. Insulating paints generally come in two forms; exterior insulating paint and interior insulating paint.

[MarkTrestt12]

It sounds like you're dealing with a common issue—air leaks around recessed lighting in the attic, even though your cans are "airtight" and suitable for attics with insulation. Since you're working with fire rated recessed lights, it's important to maintain safety while sealing up those leaks.

When sealing from the attic side, you mentioned using foam, but the way the spreaders are installed might make it tricky to get good coverage. Instead, consider using fire-rated silicone or latex caulk to seal the gap between the can light housing and the ceiling drywall. This will block air leaks while preserving the fire rating. You can apply the caulk with a caulking gun, and if the space is too tight, use a flexible extension tip to reach into the crevices.

If it's hard to work from the attic, sealing from the living room side is also an option. One approach is to use airtight gaskets specifically designed for recessed lights. These fit between the trim and the ceiling, creating an air seal without needing to foam around the lights themselves. Both methods should help reduce air leakage while maintaining the performance of your insulation.