Aside from the other people's comments, I'll agree as well. Don't exceed 13'6". I ended up with an 18" raise to get that height.
I would also like to point out that the effort required to raise a section of a bus pretty near the same effort to raise the roof for nearly the entire length. Yes, it's a little more but not by much.
So, the question I have for you is: why not raise the entire roof, then your last 8' section maybe figure out a way to raise and lower it?
If I were doing a raise/lower roof sectional on a bus, I'd weld in a rim frame with some cross reinforcement around the ribs, then carefully cut the middle out, keeping the ribs in place and securing it. That way, you have a "hatch" that is the same curvature of the bus itself.
I'd then fabricate a flange all the way around with a nice gasket (like perhaps the same door bulb seal for storage hatches or car doors) and a way to raise/lower the entire section. Stick some windows or whatever in there and that way when you're parked, you can bump it up another 4' or whatever and have a huge open space inside for your workshop. When you want to move or drive, drop it down and motor on completely legal and no worries.
Originally Posted by Gaslab
Post #2 for me and still a rookie.......I am shopping for a 72 pass.Bluebird.I have seen a lot of roof raises and add- ons,bulky and slick.My idea is to raise the last 8 feet of the roof of the bus 4 feet to act as a loft bedroom.The reason being i am going to have a small workshop underneath it.Is a 4ft raise going to make for difficult handling?