I have a 2009 ElDorado Aero Elite 250 fiberglass shuttle bus. I'm trying to figure out where I can put my roof vent.
The problem I have is that my bus appears to have three metal braces running the full length of the roof. One in the center and one a foot to either side of it. See attached photos.
Does anyone know if it's safe to cut the center brace? I don't know if they're attached to anything else or if they just run the length of the roof to increase its strength.
Some fiberglass buses come with escape hatches but they may have a different metal structure to accommodate it.
I hope that someone more qualified than I am chimes in but until then I will share what little I can.
I know that you need to maintain continuity in the longitudinal member. I have seen a number of people accomplish this by cutting the center member and "boxing" the opening.
Most that I have seen were installing a roof air but the process is identical.
They cut the appropriate sized hole in the roof, cutting the center longitudinal member in the process. Then cross pieces are placed at the fore & aft ends of the hole and abut the cut center member and but into the right and left longitudinal members. Cross pieces welded are welded in place. Finally "cripples" are sistered next to the right and left longitudinal members helping to transfer load/stress along the center member.
My 2000 Aerotech has plywood in that area and it's cut through at both the emergency exit and the roof vent. The roof is still totally rigid and I walk around up there feeling no deflection at all.
Today I took a closer look at some factory holes drilled into the metal. It seems the metal is thin with wood on the other side. I had looked through your photos Roach but somehow missed that your roof appears to have the same construction. I thought maybe yours had other metal reinforcement since it came with an escape hatch.