Insulating attic plans [View All]

[midnight armadillo]

It looks like we'll be going ahead and adding additional insulation to my mother-in-law's attic. The house is freezing in the winter and broils in the summer. IT's got your standard 1970's construction. The attic looks to have 4" of fiberglass in rough shape for R13 total...not counting pulled up areas,etc.

The first task will be to fix drafts around the house, add gaskets to outlets, etc. That's easy enough and my MIL and SIL can take care of that. The attic is 20'x40' or so. I'm thinking we'll put 2x8's crosswise to the joists and run them down the center 16" on center. Then blow in 8" of cellulose insulation everywhere (after adding soffit vents). An 8' run of 5/8" particle board down the middle over the 2x8's will finish it off.

Finally, I want to get her an attic stair cover box made of rigid insulation. I gotta find that website somewhere...

You know, I think I need to add a pair of bathroom exhaust fans too. Neither upstairs shower has one and she had trouble with icedams in past years. The new roof has a rubber membrane to prevent them but I think the cause is the shower moisture. I should do this first BEFORE I add insulation everywhere :-)

Total cost for 8" of insulation, going from R13 to R38: ~$200 for the cellulose, with a free blower rental from Lowe's since it'll be more than 25 bags.
$50 for a bigass truck rental. ~$200 in lumber costs, maybe more? ~$100 for the attic door cover (I know I could make one, but this'll be enough work as is). $550 total should do it. Plus the exhaust fans. One day for the fans, one for the insulation. Oh, and more money for the safety equipment (goggles, respirators, etc), and for a case of quality beer to bribe a friend to help. And the money for the soffit vents.

Last year she was spending $100/month on heat, with it set at 62 deg! This year it's up to $170 after prepaying to lock in a lower price. I suspect this project will pay for itself in one or two winters. ACtually less for her since I'm paying for half ;-)

Any comments, anyone? Did I miss anything glaringly obvious?