I have done a lot of remodeling to our house, but I’ve never gotten around to upgrading the attic insulation. As you can see from the main image on the post, there’s at most 3″ of cellulose up there. This gives me R-11, while code requires a minimum of R-38, which is about 11 inches – so I have a lot to add. Based on everything I’ve read, this is a no-brainer.
I guess the thing that put me off to this point was all the crawling around I’d have to do – and even worse I’d need to clean out the attic. A month ago I decided to quit being a pansy and get it done before summer.
Step 1: Clean out the attic – done.
Step 2: Make it so I could see and move around up there – done.
I already had a good sized deck up there, which was easy to work from. I cut 6 sheets of OSB into 2×4 foot pieces and laid them down over the rest of the center span of the attic.
I also got the brilliant idea to put some old Christmas lights up there. I had enough to string the entire length of the attic. I’m leaving them there after I’m finished.
Step 3: Put in the vent baffles. This was the hardest part since I had to crawl around to do it. But I get to check it off as done.
The process required me to move plywood in leap-frog fashion, crawl on my stomach, and drag everything I needed along. It took about 8 hours to complete. While it wasn’t very much fun, it was a good physical challenge.
After reading about how the standard vent baffles are too small and fail a lot, I decided to put big ones in there for max air flow. They need to be about 4 feet long to go high enough for the insulation on a 4:12 pitch roof. So I made a bunch out of 1/2 EPS foam. The cost was about the same as it would be for the little pre-made vents.
I could have used thin plywood, cardboard or foam board. Foam board won since it was the easiest to drag around and cut.
I cut notches out of the lower corners, so they would fit in between the trusses, and stapled them at the top.
I use 1/4 crown staples with plywood pieces, which held really well. At the bottom, I pushed in a bit of fiberglass batt to support the baffle in place and block any insulation I blow in from getting to the vent. The magic tool I used on this was a rake with a cutoff handle. I pulled any cellulose out from near the eave with it, then used it push the batt and cellulose back in.
Not much fun, but I got into a rhythm. Lucky I’m not a big guy – it would have been basically impossible.
I will be putting vents in between most of the trusses to get an acceptable amount of air flow. More on that in a later post.
I also had to do a bit of air sealing around the chimney, and then put a barrier around it.
As I said above I want to get to R40 or better, which means I need to blow in at least 9″ more cellulose. The attic area I need to cover is 1500 square feet – so I need about 46 bags.
I bought a pallet of 36 bags for $400 delivered, and I picked up the rest on Craigslist for $20. I have the equivalent of 50 bags. This is way better than buying the smaller off-the-shelf bags at Home Depot. It would have cost me $850 and I would have had to haul them myself.
The foam board and OSB cost about $180 – so I’m into this for about just under $600. The online calculators show the job would be around 3K to hire out.