I have had energy consultants who do blower door testing tell me their way to do them, and there seem to be 2 approaches that are seemingly at odds with each other.
First way, visually inspect the completed insulation job (closed cell foam), give tips on missed areas or problem spots, return after the house is rocked, taped, mudded and caulked to do the blower door test and infrared test.
Second way, do the blower door and infrared tests before the sheet rock is in so they can address any insulation areas or caulking needing attention.
Anyone care to weigh in? I am leaning toward doing it pre-sheet rock, but I have never had it done so what do I know!
Replies
I would think that it depends on your style of construction and where you are doing the air sealing at. Much of the air sealing on my house is done at the sheetrock level, so it doesn't make sense to do a blower door test before the sheet rock is in.
It depends on what you want to measure - the air-tightness of your insulation or the air-tightness of the finished house.
Ditto to paul45: I use the air-tight drywall system, so it would make no sense to do a blower door test before drywall and trim is installed, caulked and finished.
Solar & Super-Insulated Healthy Homes
Thanks for your replies.
Regarding using the finished drywall as part of the envelope, what are you doing differently with the drywall compared to a "standard" installation?
I am assuming (hoping) that the spray foam and caulking/sealing that the insulation contractor is doing will give me as tight an envelope as I need, but I am always interested in different ways of doign things.
With carefully installed spray foam and foamed/caulked windows and penetrations, you shouldn't need another air barrier.
I use the Air-Tight Drywall Approach with dense-pack cellulose and an exterior housewrap/weather barrier.
This entails caulking (with acoustical sealant) or gasketing each framing element to the next (rim joist to sill, subfloor to rim joist, bottom plate to subfloor, etc), and caulking the drywall to top and bottom plates and window openings and to polypans behind electric boxes. This eliminates the need for an interior vabor barrier, creates an air-tight inner skin to the thermal envelope, and still allows drying to the inside during summer as well as to the outside during winter.
http://southface.org/web/resources&services/publications/factsheets/24ada_drywal.pdf
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