Installing insulation bus conversion part 5

We decided on using foam board insulation for the floor, walls, and ceiling (1.5” r7.5). Spray foam may be better but Is more expensive, fiberglass can hold moisture and mold and fall apart as we found when removing the stock insulation while gutting the bus.
I also cut wooden ribs to fasten our ceiling to to create more of a thermal barrier rather than screwing the new ceiling to the steel bus ribs allowing outside temperatures to transfer more easily, it may not make much a difference but I figured I’d try it.