We experienced significant water damage to a wall in our very old home before we had our roof replaced. We had professionals check structural beams, framing, et cetera when the roof was replaced.

Now we want to replace a whole section of the wall plaster with drywall. All that's there now is lath and cellulose insulation. However, some of the cellulose has "leaked" out of the wall and I'm not sure what to replace it with.

I considered Dow "Big Gap" expanding spray insulation, but I'm not sure it is the best choice... the spot needing insulation is about 1' x 2' and this wall is angled and directly under the roof. Even with lath there to hold the foam up until it cures, I'm not sure canned spray foam is ideal considering its suggested use is for filling cracks, not large voids.

I can't imagine fitting a sheet of fiberglass insulation in there because we don't want to take down the lath and the rest of the cellulose with it. It seems unlikely that we'd have an easy time stuffing more cellulose in there due to the gaps in the lath.

Suggestions or related experiences to share, please!!