Tyvek for air sealing non-IC recessed lighting
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| Posted in Energy Efficiency and Durability on
Renovating our new to us 1975 built home, upgrading our attic insulation to R 60, along with air sealing the opening into the attic. The openings include several recessed non-IC light fixtures. They are properly protected for insulation to be installed. To air seal them I plan to use Tyvek on the outside of the protective structure and seal it to the ceiling sheet rock. Is their a better material ? Is this a good way to air seal them.
Les Otte
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Replies
Drywall boxes caulked over them is all that most do. It is detailed on this site somewhere, it may be searchable here and Google.
Tyvek is not a great air barrier - an air barrier must be rigid. What are they "properly protected" with? This should be your air barrier - drywall or rigid foam boxes. Be sure to make them large enough that your can lights do not overheat. We recommend installing CFLs or lower wattage bulbs after the boxes are installed to help control the overheating.
Les,
I agree with AJ and Danny. Build your boxes out of rigid foam or drywall, and seal the edges of the boxes with canned foam or housewrap tape to make them airtight. Be sure to glue them to the existing ceiling drywall (from the top, of course) with canned foam.
Thank you for your guidance, I will build the airtight fixtures out of 2 inch ridge foam leftover from enclosing the heat pump air handler in the attic ( I am enclosing it to bring it into conditioned home space). Currently they are protected by 2x12s as the vertical component above the ceiling drywall and the top of this enclosure has metal screening, the whole enclosure has aluminum foil covering it, and topped with 3.5 inch fibber glass batting. I plan to remove the fiber glass batting and replace it with the ridge foam enclosers sealed to the drywall. Should I leave the aluminum foil or remove it?
The fixtures themselves are vintage 1975, and as recommened I will use CFL lamps. Being older fixtures the wiring is likely rated for only 60 degrees C, I will call the manufatrure to confirm the fixture wire temperature rating.
After installing the riigid foam fixtures, the R60 insulation will be installed over the whole area.
Les Otte