Better to compress attic blow-in fiberglass, or remove it?
I’m going to be laying a subfloor in my attic, where fiberglass has previously been blown in between the joists.
The blow-in insulation is currently thicker (deeper) than the joists, and rises several inches above the top surface of the joists. To lay the subfloor, I’m going to need to either compress the fiberglass between the joists, or remove the amount that extends above the top of the joist.
I know compressing fiberglass decreases its effective R value, so I’m wondering whether it’s better to compress what’s there, or remove it and have less fiberglass, that is not compressed!
Any advice would be appreciated!
(Edit: I know that either of these options, compressing the insulation or removing it, will decrease the R value and are therefore bad from a thermal performance perspective. I plan to add mineral wool batts between the rafter and gable end stud cavities to remedy this.)
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