Found and caulked the leak. It was in a corner of a window. I had appeared to be coming through the Great Stuff, but I now realize it was only coming over it.
With that scare behind us, we finished laying the insulation.
We covered our 1″ polyiso insulation with 3/8″ plywood.
The plywood is attached to the bus with 2″ sheet metal screws. We staggered the sheets of plywood and insulation so the seams are not on top of one another.
And of course, more Great Stuff in the gaps.
Next up is the roof deck. It’s not clear what we’ll be able to do with the weather this week, but we’re waiting until the deck is done before we begin the interior.