"Honest Building Science question on this topic: If the drywall of the knee wall is well sealed (meaning outlets, top and bottom plates, etc) as well as the floor joist below, if there are fiberglass batts in the knee wall, is is really that…"
"You caught me being lazy, I don't have time to go look up the ASTM air barrier test it passed at the moment. The material can be left exposed, it's inexpensive, it provides an air barrier, it's easy to install - I like it as a…"
"The purpose of it is more to seal the fiberglass enough to reduce convective losses. It's perforated to prevent a double vapor barrier. It's much easier to handle, drag into, and install in small knee walls than foam board. It is an air…"
"Sort of. 3.5" fiberglass batts can be R-11, R-13, or R-15. An R-15 batt weighs a ton in comparison to R-11. You have to get in the 2-2.5 pounds per cubic foot range to get over R-4/inch with fiberglass. If you squash an R-30 batt, you lose…"
"James, you could use a better tone there...
Like I said, that was early on. I used fiberglass because the cavities were chock full of knob and tube that I wasn't going to change. I didn't know to block the joists yet. We are in a practice…"
"I used to work for Guardian Building Products, they sell a perforated reflective insulation called Solar Guard. Here is a copy of a tech bulletin they did. The houses aren't truly apples to apples, but R-13 with Solar Guard over it performed…"
"I agree with Alan, and Scott and Dale as well.
Energy prices, over the long term, aren't going down. China and India are industrializing with upwards of 2 billion people to the paltry 300 million in the US. We're about to start…"
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