We recently acquired a 2016 Greyhawk 31 FS that had an interior fire. The fire appears to have started on the bunk inside the slide out. The damage is the worst on the ceiling as the thin plywood and styrofoam are pretty easy the burn. Most of the styrofoam melted/burnt, even if the plywood didn't. It was able to burn and melt between the layers. We will start demo this week, but looking for advice on the best way to rebuild the roof/ceiling construction as I know it is vacuum bonded from the factory. I have considered spray foam as an option but someone with experience would be much appreciated.