For some reason, I took a closer look at the insulation in the rim joists. Not only was there not enough of it, it was in bad shape. Some had been installed backwards (with the "interior" side facing the exterior). It was falling apart, and didn't provide any airflow protection. That's not too bad, except I found several large gaps to the outside.
A little explanation. My house is built so that the basement is only half-underground. The upstairs is attached to the foundation, but the front extends past the foundation. That makes the upstairs larger than the downstairs. That also means that a few feet of upstairs flooring are "exterior walls". The gaps I found were where the bottom plate joined the upstairs wall. Siding and trim hid the gaps from outside, but from inside, you could see daylight.
And so I added re-insulating the rim joists and caulking air gaps to my list of things that needed to get done.
But first, the electrical wiring needed some sanity. The basement, which had essentially been a single room, had receptacles on at least four different circuits. All of those circuits (except for possibly one) also powered receptacles upstairs. One of those circuits also powered the basement lighting and several lights upstairs. Awesome.
That awesomeness was partly driven by convenience. The original receptacles were mounted in boxes that were poured into the foundation, fed by wire in conduit that was also poured into the foundation. For convenience, the builders simply connected the basement receptacles to the upstairs receptacle right above.
Why, you might ask, is that more convenient than running one or two circuits for the basement? Because the basement exterior walls were never framed. The walls were drywall glued to expanded polystyrene (the white stuff) glued to concrete. Yup. So framing got added to my list of things to do.
Anyway, electrical. I spent several hours disconnecting receptacles and pulling out wiring as best I could. Except for one problem, everything is in good shape. That one problem is the basement closet, whose wiring is wedged into place and has an open splice in the subfloor (to feed a basement receptacle and the doorbell, of course). Disgusting, unreachable, and needs to change, somehow. I'll probably drill through the wedged area to free it up, then replace the wiring. I don't really want to leave it hanging.
But the wiring is nearly gone, meaning I had a blank slate to start with: bare concrete, no wiring, no insulation.
On advice from a friend (and from Reader's Digest's basement finishing guide), I bought a stack of 3/4" extruded polystyrene (the blue stuff, not the white stuff that gets used for packing material) and glued it to the foundation walls (*). Believe it or not, just having the debris out and the foam on the walls makes it look a lot more like a room.
Since I was already filling up the basement with adhesive fumes, I also went ahead and caulked the gaps I'd found to outdoors. I followed the gap-filling advice from the "Matt & Dan Show" (**), which is to "silicone the heck out of it".
Now, with the exception of insulation in the rim joists, the R-value for the basement is as high as it ever was. That'll get even better when it's framed and I add some fiberglass. I haven't decided yet whether it makes sense to go R-13 on the entire wall, or R-13 below ground level and higher R-values above ground level.
Upcoming tasks (all of which appear to be framing tasks):
- Buy framing materials (2x4s, nails (for toenailing), screws (for overhead blocking and top plate), construction adhesive).
- Borrow powder-actuated nailer (to make installing the bottom plates quick, easy, and loud).
- Install overhead blocking on long wall.
- Install bottom plates on short walls. Then install top plates. Then install studs. Properly frame front windows.
- Install bottom plate on long wall. Then top plate, properly framing ductwork soffit. Then install studs. Properly frame windows.
- Consult my lovely bride on location of wall dividing office and family room. Mark location. Install bottom plate, top plate, studs, and frame door.
* Using polystyrene-safe adhesive. Rumor has it normal construction adhesive will either melt it or not stick. I'll have to experiment on a piece of scrap.
** The "Matt & Dan Show" was the adventures of and commentary by my friend Dan and myself when we were paired up to do Primestar conversions to DirecTV, DirecTV installations, and other various jobs in high school and early college. Nothing was ever actually recorded, but we needed something to keep ourselves sane given some of our encounters.
