Another area I worked on I remembered my auditor say there was a lot of leakage coming in. Its the opening to the sunroom which is an addition. So, the wall is the old exterior wall. It is also the old corner of the house which I think doesn't help much.
So, first I pulled all the trim off of the opening.
The top of the opening is made of two lvls spaced apart. And... looking above shows the balloon frame design that goes up and up and up. Well, at least after I pulled out that bunched up fiberglass. Anyway, I thought about how I was going to seal that up and... well I didn't come up with anything great.
So, I cut into the wall above it to get at things properly.
A little sawzall action shows the late 1800s "insulation" that was used on the house. Its another layer of lath and plaster between the inner and outer wall. Not a horrible idea in theory, but after 100+ years it begins to leak air like crazy.
So, I'm still looking for the best way to seal and now insulate this area. I'm open to ideas, but I think I'll probably just cut out as much as the lath and plaster as I can and just shove some rigid foam up there and foam around it.