Thursday, July 9, 2009
This Old House re-runs
When Aimee and I bought this old farmhouse we only had time to do about half of the work we needed to do in terms of rebuilding before we had to move in.
If you check out Aimee's page of photos here, you can see what we did manage to get done. It was quite a bit of work -- and that was a summer I worked about 45 hours a week at the college too. But we concentrated on the interior, although we also blew 2 feet of cellulose into the upper crawl space and later that year rebuilt the attic above the kitchen with two layers of R19 fiberglass.
One of the jobs that was saved "for later" was rebuilding the exterior walls of the house and adding insulation. The house had vinyl siding when we bought it, in a sick shade of green. Even so, the exterior, with the vinyl, was more or less bombproof on the outside and could safely be left for a while. But we knew we wanted a super-insulated house.
Eventually, as we could afford it.
This week I began the job of rebuilding the exterior walls. I'm adding both 4 inches of cellulose inside the walls and 2 inches of pink foam board insulation outside. There is 1/2 inch shiny foam board insulation on the inside already -- done before we moved in as we replaced the drywall. The inside insulation has the 3/8 inch airspace that bumps the value up to R6.1, so with the R15.2 of the cellulose (studs are actual 4 inch rough cuts) and the R10 of the pink foam and two inches or so of wood, we will have roughly R34 walls. The ceiling of the main house is already more than R60 with the two feet of cellulose (R 3.8 per inch).
So when this new job is complete we will not quite be officially super-insulated. But still, we should be nice and warm.
The first part of the job was to wreck out the parts of the old wall we were not going to keep. I removed the vinyl and it's underlay. Then I tore out the bottom few siding and sheathing boards, which I removed to inspect the sill -- nice and sound after 109 years -- and plan to replace with PT plywood, while adding lots of sealant and carpenter ant repellent.
Moisture and carpenter ants will do for an old house in Maine very quickly. We had already to trade out part of the sill on another wall because of ants, and I'm very careful now to spray the pyrethrin-based repellent compound each spring all around.
This job has to completed before Saturday's predicted thunderstorms to be on the safe side, so I'm under the gun.
Here's the kind of mice nest we find in these walls when we take them apart. I used rubber gloves to get this out. There was even a bat sleeping under the vinyl. He was pretty groggy to have to come out in the daylight.
Then there's a shot of the completed wrecking job, the sills all nice and clean.
The next thing I did was drill the 2 inch holes for the cellulose blower at the top of each stud bay. Then I stuffed fiberglass in the spaces under the windows and closed it all in with PT plywood and glue and nails from the nail gun.
This morning first thing, I will go get the blower machine from the rental yard. I have today and Saturday to get the wall closed in again before the rain.
Once the new foam and sheathing is up, Aimee will shingle the walls with cedar shingles. She's an excellent shingler, and not too shabby a finish carpenter either.
But she doesn't like framing, or what she calls "big jobs."
This is a fairly painstaking way to do this work, with all the checking of structure and glue and sealant, and then the time-consuming shingles. But when we done these walls will be good for another hundred years, or more. The materials we're using are modern and more inert than the pine and hemlock that have brought us thus far, and not as tasty to critters. Cellulose is actually impregnated with Borax which repels insects. The new materials are also put together differently: tighter, sealed better, well insulated.
This is definitely the way to go.
I realized yesterday that I don't perhaps need to be quite as worried about my firewood pile this winter, because if I can get this job done, we won't need as much firewood. Or heat oil, either.
Now that would be a good thing.