Tyvek is a lot more than that too… We use a TON of it for bags or part of bags for medical devices that are sterilized; it’s gas permiable (sp) so it lets the sterilization gas through; but still keeps a sterile barrier after exposure.
Not to thread jack, but I don’t think we need 2 insulation threads.
So I just had a tearoff roof done, which gave me an excuse to finally clean out the closet with the trapdoor enough to make it up into the attic beforehand and check out the plywood. Good news was, the plywood was in good shape, (and the roofing company didn’t have to replace any 
) Bad news was, there is NO insulation up there whatesoever. :picard:
Lowe’s is having a pretty decent promo on insulation right now, sale prices and get a $100 gift card back when you spend $400 on fiberglass insulation, but I’ve heard retail markup on it is so bad that you can hire a pro and still actually save money, since they can get the stuff so much cheaper at wholesale.
Anyone have recommendations on either
1.) A company to do the insulating or
2.) Someone that installs as a side job if I buy it myself?
I dealt with installing this shit in an attic once. NEVER AGAIN. Shit burns worse than Devil’s Springs.
Check Urban Insulation, they tend to have good prices.
Probably a little late to add any worthwhile info, if it’s even worthwhile… My house was built in '46. I went to install some cable jacks and outlets, and found a small bit of rock wool insulation in the base of the walls, but nothing above it. I ended up buying 7 bales of the blown cellulose stuff, coming home, drilling holes in my drywall, and finding fiberglass insulation.