This is how I'm planning to execute my roof raise. The spacers are based on a suggestion in Ben Rosander's
Select and Convert Your Bus on a Shoestring. He also recommends staggering these spacers vertically so they don't line up down the length of the bus (otherwise you're giving a place for the sidewall to "fold" in a rollover; a chain is as strong as its weakest link). The angle iron is my idea for bridging the spacer and reinforcing the post.
Welds would be along the length of the angle steel and at its ends (and of course at the junctures of the spacer and original bus frame rib). One caveat is if you use angle iron of about 1/8" thick, you lose 1/4" space between adjacent ribs/studs and I'm guessing the bus windows wouldn't fit anymore.
To paraphrase Rosander's warning at the beginning of his roof-raise chapter, if you aren't proficient at welding and precision work like this:
- Learn how to do it from an expert.
Find an expert to raise the roof for you.
Don't raise the roof.
For me, that last one would mean either to become accustomed to stooping or find a high-roof bus. When I stand up straight while wearing shoes, the top of my head is about six inches higher than the middle of the ceiling of a standard school bus.