What are the drawbacks to a partially filled stud cavity with BIBS to reduce damage to drywall from cellulose?
I have no experience with dense pack fiberglass, and many claim it is equal to cellulose in insulating performance. I realize there are other attributes to consider, but I’m focusing my question on a specific problem or rather concern.
So my drywaller is concerned with our choice to use dense pack cellulose in the stud cavities. He says that it leads to many callbacks, due to screw pops, cracking etc. He says this happens, even in old homes that are being remodeled where the wood is dried out, and not moving like it does inherently in new construction He is a very reputable guy, and does extremely good work, so I believe him….
The insulation contractor states that the drywall contractor is correct, and there are known issues with dense pack cellulose causing problems with drywall install afterwards. He subsequently encouraged me to use dense pack fiberglass instead and guarantees that BIBS won’t bow the drywall, and shift downwards due to gravity like dense pack cellulose does. We discussed wet blown cellulose, but he isn’t a fan of “the moisture specifically”.
I then discussed this with my drywaller, who further encouraged me NOT to use ANY dense pack product, or if I was dead set on it to only partially fill the cavity since I have more than enough exterior insulation.
Side note: We weren’t going to fill the walls at all, but were encouraged to by folks who have built using just exterior insulation. They stated that the walls acted like a drum because they were empty, and ended up having to blow-in cellulose after the fact to correct the sound issue.
I’m building two structures (a house and a barn/workshop/garage/apartment). The garage/barn has 2×6 walls, and the house has 2×4 walls. The garage has 5.5″ of EPS exterior insulation and the house has 8.75″ of EPS exterior insulation. The air barrier is outside the sheathing.
So even on the garage if we fill the 2×6 walls we are at a 50/50 ratio of interior/exterior R-value which in Zone 6a I feel ok about. The house we are at an acceptable ratio too. My concern is primarily with a cavity only partially filled with a fiberous insulation. Never done it, should I be concerned? Is there something I’m missing here? Do you have experience with dense pack vs. drywall – who wins?
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