Questions about insulating attic and reclaimed insulation
I recently had an energy audit on my house and increasing the insulation in the attic was a top recommendation (Currently there is about 2 inches of cellulose plus a layer of batts, but they’re disturbed and a mess all over due to previous owner’s wiring work).
My plan has been to remove the cellulose and batts, clean it up, fix the attic ventilation (currently no soffit vents, only gable, and it gets very hot), air seal everything with foam (there are lots of gaps and holes, and lots of insulation dust filtering down) then put back down enough insulation to get me up to the recommended R48-R60.
Doing that with blow in fiberglass (what I originally planned) is about $1200 for the batts alone (about 900 sq feet). That doesn’t include rebates of ~$400
Someone on this site mentioned to check into reclaimed or factory second insulation locally – on local classifieds (https://classifieds.ksl.com/listing/50898559) I found reclaimed polyiso for $10-$20/sheet (2″, apx R-14) If I can get it at the lower price that may be much cheaper, although I’d have to do a lot of cutting and sealing to put it into joists and fit it into the attic (not a problem, I have a few hard working teenagers eager to put to work 😆)
So my questions are:
1) Is there any concerns/risks with putting polyiso roofing insulation in the attic floor (maybe off gassing, etc?) Or since the roof space should be vented is it less of a concern?
2) Is there concerns with layering multiple layers of polyiso? I’m also slightly concerned about the loss of insulation at lower temperatures (I’m in Utah, so it will get down to freezing, though not usually much below, in the winter).
TIA – I Appreciate the posts on this site, have been super helpful.
Here’s a pic of my current attic for reference – as you can see, the insulation is all over and not very deep.
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