I installed 4" non IC LED recessed lights in a first floor room with 8" clearance during a remodel (no insulation and full access to ceiling space). I later realized that one area of the room with a few of the lights has a small angled roof space above it and needed to be insulated. Rather than switching the housing types, I purchased some tenmat covers. The internet tells me that I need to air-seal them from heat escape (live in Northeastern US), but I need to insulate before the sheetrock goes up. How would I airseal edges with foam after the ceiling goes in? Can I just tack the covers to to the rafters to hold them in place and not airseal? Their datasheet doesn't say anything about foam. I'de rather risk losing heat than have poor airflow and hot fixtures. What should I do?

1 Answer 1


What you should do is forget about using those crappy dunce caps and ensure that the fixtures are at least 1/2" away from any wood or combustible material and that insulation is removed and kept away from the fixtures, at least 3" clearance.

  • So the heat leakage is not an issue at all, just fire hazard concerns is what you are saying.
    – Drai
    Commented Sep 8, 2016 at 11:25
  • Heat leakage is a concern but is trumped by issues related to overheating. Those caps may be listed as fire resistant but I have heard that they cause the fixture to heat up, which could cause the thermal cut-off device to turn the fixture off or cycle on and off. Non-IC fixtures by code must keep 1/2" from combustibles and 3" from insulation, I am dubious that use of the covers nullifies the requirement. Commented Sep 9, 2016 at 1:18

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