After ripping down the ceiling in the basement, our suspicions were confirmed. Our house, built in 1916, was constructed using Balloon framing - not the platform framing style used today.
What does this mean? (This may sound too technical) The wall studs run all the way from the sill to the top plate in the attic. The second floor joists (our weak 2x6s) are nailed to the sides of the studs, rather than having the studs stop in a top plate and the joists sitting on those as is done today. Balloon framing was used very little after 1930 because of the difficulty of finding good, long old-growth wood pieces and the fact that balloon framing was a fire hazard.
Scott and I tested this open framing style last weekend by going up into the attic and pulling out about 4 inches of insulation on one of the exterior walls. Then, with Scott watching in the basement below, I dropped some plaster pieces down the chasm. "Ouch! Quit throwing things at me!" came floating up to me from below. Sorry Scott :)
Not only did we verify the balloon framing, this test also told us that there is absolutely no insulation between the studs of the exterior walls!! Its amazing our house stays as warm as it does on the first floor. That plaster/lath must be a good insulator (then again, we haven't received our first gas bill yet).
So I did some research on adding insulation and we are thinking about using blown-in cellulose insulation (click for details) which turns out to be:
- great for retro-fitting
- environmentally friendly (made from treated recycled newspaper)
- more effective than traditional insulation
- Most importantly, cheaper! :-)
We'll wait to do this until we start ripping out upstairs though.