Consequently, since we knew we didn't have a block of time big enough to do everything at once, I figured we could do the soffit by itself and leave the fascia and gutter part for later. So here's what I found when I started removing the old aluminum soffit: 3/8" plywood underneath. It appears that the plywood was the original soffit material 50 years ago, and the aluminum came along later (maybe 30 years ago?) and was applied over the top (or underneath as the case may be).
I actually knew about the plywood from removing the soffit in a few places for various other projects over the past year. What I didn't realize was the water damage that had occurred over the past who-knows-how-many decades as water would get trapped above the plywood and between the plywood and aluminum.
Here's the culprit. You're looking up at the bottom of the roof from where the plywood soffit used to be. The white board at the bottom of the photo is the painted bottom edge of the fascia; the dark grey wood above that is also the fascia board; and the yellow 2 x 4 on the right is the end of a rafter. The light-colored strip just above the fascia board is the bottom side of an aluminum drip edge for the roof. You're not supposed to be able to see that from the bottom. You can see that the roof planks don't go all the way to the edge of the roof, nor is there any kind of barrier under the drip edge. As a result, rain water seeps up under the shingles and runs over the top of the drip edge and into the soffit area.
In case you haven't put it all together yet, that means one more project before everything works the way it should. The tally now: (1) tear out and replace soffit, (2) tear out and replace fascia and gutters, and (3) fix roof and drip edge.
The good news is: this is what the new soffit looks like after the plywood and old aluminum are removed, and the new J-channel and soffit panels are installed. Sometimes I like to just sit and admire how beautiful it is ... until I notice the old fascia and gutter. We are not done with all the soffit demolition and replacement yet, so we won't be tearing into the gutter just yet.
One other blessing is the pile of aluminum we are accumulating. Add all this soffit, fascia and gutter aluminum to the old aluminum window frames we tore out last year, and we could have a sizable scrap payment one of these days!
I wanted to include a photo of this observer. This praying mantis sat on this piece of soffit for three days before I got concerned that it may lay some eggs on the soffit and give me one more project to take care of....