Re: RV air conditioner install issues on bus?
One issue you may have is that the metal is thin and the wieght of the AC will bend it. I think many people (including myself) put some sort of bracing between the layers of the ceiling and roof to take up the space and prevent the sagging of the upper roof metal. Although a little bit of sagging may actually help level out any curvature. I cut some 2" pieces of wood and used that to fill the gap and attach the upper unit to the roof.