I looked on the Internet to see how other converters had dealt with the low bus roof and discovered that a few had actually cut the thing completely loose, only to lift it about six inches. I felt that if I would be going through the work of cutting the entire roof from the rest of the bus, then I might as well raise it enough to have a shop under the loft bedroom in the back.
I considered wind resistance, though, and kept going over design ideas in my head. I could cut the whole thing off and raise it the entire length of the bus, but this meant the face would have a MASSIVE forehead. In other words, the place above the windshield would be so high that it would cause immense amounts of drag at highway speeds. The other option was building two sloped transitions. The first would extend from the existing front edge of the roof, a half-moon shaped panel about 12 inches tall at its greatest height, to the next section of roof, about two feet taller. This way I could keep the wiper motors and electrical stuff where it was and wouldn’t have to do any sketchy reworking. The second transition would begin about one third down the length of the bus and move into the next section of roof, another foot taller yet.
This would bring the total height of the bus to about 13 feet, one inch. This is about six inches below the legal limit. I made sure to leave a little room in the case my tires were a low at the time of measuring. It would be pretty disheartening to have to cut the whole thing apart because I was half an inch too tall. Raising the roof this way gave the bus a gradual look that I thought would be more aesthetically pleasing, as I didn’t want to ignore the exterior appearance of the bus. I wanted something that looked different but was still easy on the eyes. Now that we live right beside Highway #1, my eyes are constantly assaulted by the look of the modern RV – a huge blob of ugliness that the manufacturer tries to mask by painting some Nike-like swooshes on the side. YUK!
Perhaps this is a good time to explain how these buses are constructed. This particular bus is an International truck cab and chassis with a Thomas bus built onto it. What happens is that International builds half a truck and sells it to Thomas, which then finishes the body on the chassis to create the bus as we know it. So, in the engine compartment you can find a tag that has the serial number, date of manufacture, and that sort of stuff for the truck, then on the inside of the bus, normally on the roof panel above the driver, you will find another tag giving yet another set of information about the vehicle, this time from Thomas. I got rid of the Thomas tag and am going to insure this vehicle as the International truck that it was to begin with, only customized into an RV.
Structurally, the school bus is quite a simple thing. It starts out as just a hood, dash, steering wheel, and frame when it comes from International. Thomas then adds a sort of steel decking to the frame. It is important to know that this deck is not simply a giant flat piece of metal but rather many pieces of sheet metal that are bent into a piece that is about a foot wide and two inches thick. These are cut to fit the width of the bus then placed perpendicular to the frame and bolted to it, similar to decking on an outdoor deck. It takes quite a few of these to cover the entire length of the frame. Then the wall and roof frames are made from bending channel into a huge upside-down U that gives the bus its dome-like shape. They are continuous from one side of the floor, up over the seats, and down to the other side of the floor and are welded to the steel decking. Then the outer metal skin, roof skin, and interior skin, as well as the electrical systems, windows, doors, and other interior fixtures are installed. Finally, 1/2-inch plywood is placed over the metal decking and covered with ugly vinyl flooring. A bunch of seats finish up the school bus. (Note – this version of events may not be entirely accurate, as I have never been to a Thomas plant to view the action firsthand. I am only describing what I have seen in dismantling a school bus.)
How I raised the roof – rear section
From my preliminary drawings, I had some idea of where I wanted to make the transition from the rear (highest) section of roof to the front (lower) section of roof. I did some measuring to find this approximate point on the roof and made a mark; this was not a cut line, it just gave me a general idea of where to put this transition. As mentioned earlier the buses roof consists of frames that are spaced about every two feet or so down the length of the bus. The sheet metal that covers the roof on the outside is attached to these, as are the sheet metal pieces that make up the finished ceiling surface. So the next step was finding the frames in front of and behind my mark. I then cut out the panel between those frames and was left with a two-foot gap in the middle of the bus roof. Now the rear section of roof was independent from everything else (remember, I had already removed the entire back wall) except the framing channels between the former window openings.
A piece of 1X2 tubing just happened to neatly slip inside the steel U channels frames. I determined how long my extensions needed to be for my new roof height and cut them, allowing some additional length so I could run the tubing down to the old windowsill. I figured the extra strength was worth the money. Then came the scary part.
On the web, I read how people had constructed complicated frameworks around the bus then cut and lifted the roof with come-alongs, winches, or even car jacks. But I figured that they didn’t have a huge tractor at their disposal – the advantage I had by converting this bus on my father-in-law’s farmyard.
The theory
What I wanted to do was drive the tractor perpendicular to the bus, raise the bucket high above the roof and drive forward until the bucket was centered lengthwise over the section I wanted to raise. I would then lower the bucket so it was just above the roof, wrap chains under the roof section and over the bucket, then put some pressure on the roof by lifting the bucket until the chains were snug. Once this was done, all I had to do was cut through the middle of the U channel supports, leaving a piece of the frame sticking out from the bus and a piece hanging from the roof. Once the roof was loose, I could weld my supports to the frame ends that were left on the roof. Then I would lift the roof and put it back onto the bus, sliding the 1X2 tubing neatly into the framing channels.
The practice
This all seemed to work well in my head but after cutting the supports, I was faced with some serious problems. The first was that the bucket of the tractor couldn’t actually lift the roof as high as I wanted it to go. The second was that it was extremely hard to centre the chains properly so that the roof would stay somewhat level once it was loose.
After realizing I couldn’t address these problems while the roof section was just dangling there, I managed to gently set it back down on the bus and detach all the chains. I discovered my father-in-law had built a bucket extension for one of his projects and that using this would allow me to lift the roof to required height (this wouldn’t be the first time he saved my ass). But I still had the problem of keeping it level. I also didn’t want to do any welding on the roof while it was grounded to the battery of the tractor, which could cause irreparable damage. So after a couple of hours of thinking and discussing with Earl, we reached a solution.
I screwed four 16-foot 2X4s vertically to the sides of the bus at each corner of the section, inset by a few feet. I then screwed an eight-foot 2X4 to the two rear 16-footers, passing it directly underneath the roof to support that end of the section, and repeated this in the front.
With my father-in-law controlling the tractor bucket, we reattached the chains to the front part of the section and raised it a couple feet. While he held it there, I moved up the eight-foot 2X4 along the 16-footers so it would continue supporting that section, then we did the same in the back. (Unfortunately, the first time we tried this, the front eight-foot 2X4 collapsed when we raised the back end of the roof section, so I had to add more cross bracing and more 2X4s to increase the strength of my supports.) We FINALLY had the entire section level at the correct height and I reinforced everything with more lumber. This episode took an entire Saturday. 
The bus sat like this (picture left) for almost two weeks until I got the money to buy the 1X2 metal tubing. Once I had that, it was a simple matter to slide the tubing into the U channels and weld everything in place.
Some other considerations
At this point in the process, we decided it would be a good idea to move along the construction of the bus as quickly as possible, so we went into debt and get a loan. In hindsight, I don’t think this was a wise decision because the money didn’t get us very far and now we have payments, as well as having to try to pay for the other parts and materials we need. On the other hand, if we hadn’t taken out a loan, the bus might still be sitting with 2X4s supporting the roof.
About $8,000 paid for the steel needed to raise the roof, our windows (about $3,000), brake parts, a 30,000-pound jack, random heavy duty mechanics tools, filters and fluids, lumber and plywood for the floor, other various materials, and the bus itself.
Also at this point, I decided to build the floor of the loft in order to add strength and rigidity to the structure before raising the front section of roof. I simply determined the height I wanted the loft to be and welded two pieces of 1X2 tubing along the walls at this height. I then welded in a piece at the front and back of these side pieces to give the loft its forward and rear limits. I made sure to leave enough room at the back to accommodate the new wall that I had yet to build.
How I raised the roof – front section
Just as I had to remove a ceiling panel in the middle of the bus for the rear transition, I had to remove the panel above the driver’s seat to make my front transition I made the forward cut along the edge of the roof’s first frame member (the U channel) allowing it to continue giving structural strength to the front wall that housed the windshield. I made my second cut along the edge of the next U channel and removed the piece of sheet metal. I also had to cut out some cross bracing welded between these two supports. At this point I was left with the front wall of the bus intact, including windshield and about 10 inches of the original roof, then a gap of about two feet, then the rest of the roof.
To lift the front third of roof, I didn’t need the bucket extension on the tractor because I wasn’t going as high. I followed the same method of centring the bucket over the roof and attaching the chains. But this time, I managed to cut the roof loose and clamp the extensions in while it was still swinging from the bucket. This was also a chore because as I mentioned earlier, the roof, after being cut loose, hung from the tractor completely out of level. I had to maneuver one tubing extension in the corner that hung the lowest into position using large steel bars to get it to sit in the U channel properly. Then I slowly lowered the rest of the roof and maneuvered the extensions into position one at a time.
Conclusion on raising the roof
Finally, the bus roof was at the two heights I wanted. If I were to do it again, though, I think I would have taken the advice of the folks on the net and possibly done away with the whole tractor idea or at least done some measuring of the tractor’s maximum lifting height to get an idea of what was involved before I started. It was dangerous and it turned out to be a lot more work than it had to be. As an alternative, I could have built a wood structure/scaffold around and over the roof and used some winches to carefully lift the roof a little at a time. It would have been more time consuming but may have given fewer headaches in the end. Also, when I slung the chains under the roof they bent the little gutters that run along the bottom edge of the roof above the old windows. This is a bit of a bummer because I was hoping to terminate my new exterior metal skin under this gutter and now I have to cut out the damaged stuff and weld in new pieces (assuming I can get some from a wrecker). I also want to get enough from the wrecker to patch in pieces where the angled transitions will go, as the pieces on the sections of roof I removed are too short for the length of the angle.
It took me three days to: weld in the extensions for the rear section of roof and remove the lumber supports, weld in the loft, remove the front roof panel, raise the front section of roof, weld in the tubing for the front section. (At this point, I was still pretty new to welding, so that took me longer than it would have a more experienced welder.)
Transitioning between three levels of roof
The transitions were a bit tricky to frame. To determine what each 1X2 tube frame member would look like, I used string lines and masking tape to lay out its shape. Then I measured the string lines to get my measurements.
I installed four new slanted pieces of 1X2 tubing between the rear and front sections of the raised roof. Each end terminates on the face of the framing members of the respective roof sections. This makes for some fancy cutting but will make a nice clean transition when I am finished. I also hope to weld in cross bracing between these to make sure they act as one roof, not two joined by a weak bit of framing. For this I hope to use 1X1 tubing. I did basically the same thing at the front of the bus. From the front of the forward section of roof I laid out, cut, and installed slanted pieces of 1X2 tubing in the same manner as the rear transition. Each end is welded to the face of the frame that is exposed on the front of the roof section. However, the lower ends of the
tubing landed on top of the little section of roof that was left above the windshield. I simply cut a level line on the tubing so the pieces would sit flat on the roof and welded them to the sheet metal being very careful not to burn through it. This seemed to work pretty well. I also hope to put in cross bracing here but I will not be able to go from corner to corner as I bought some smaller windows to go in between these framing members. I may double up the slanted pieces so they will be stronger and hold the sections together better. I may also put cross bracing above and below the windows to give a little extra strength.
I knew I wanted both transitions to have the same angle or it would look pretty goofy, so before doing any roof raising or anything I figured out how much horizontal distance the front transition travelled, as its limits were not going to be moved as easily as the rear. The forward limit was the absolute front of the roof and the aft limit was the second frame member. Once I knew how high I was going to lift the roof, it was a simple matter of using Pythagoras and some ratio-and-proportion to compare the front triangle to the rear to determine the exact horizontal distance the rear transition needed to travel to get the exact angle. I am not going to explain all the math, just look it up in a textbook or e-mail me if you really need to know.
Saying this may contradict what I said earlier about raising the roof. I made it sound as though both panels that I removed were between frames of the roof, when in truth this is not entirely accurate. Because the rear transition was the same angle but did not have the same dimensions as the front transition it did not land exactly between frames. If you look closely at the pictures you can see that the upper limit of the rear transition is a few inches in front of the frame. I fixed this by welding in some spacer blocks to make a sturdy point for the transition framing members to be welded to. I didn’t mention this in the description for simplicity reasons and if it still doesn’t make sense don’t worry about it. Just e-mail me if you need a better explanation (address under Profile tab).
Scribing the sheet metal
This job must be done with precision and attention to detail or the piece of sheet metal will not fit with the object you are scribing to. Practicing with a piece of scrap cardboard or scrap metal is essential. This piece should be quite large and flexible. I screwed together two pieces of the ceiling material and laid this sheet on the transition and slid it down towards the highest point on the lower roof. Once the piece made contact I temporarily attached the sheet metal to the framing with self-tapping screws. Then I took my “compass” (I welded two metal rods together to make an inverted V then t
aped a marker to one end) and held it so that the end without the marker was against the edge of the lower section of roof on one extreme side of the roof. Then I carefully set the marker side down against the test piece. Slowly and carefully I pulled the compass across the sheet metal and edge of the roof making a mark that mimicked the curve of the lower section of roof. Once I got to the end, I checked it once more to make sure I was accurate. I had to cut the stiffeners that run along the top of the bus roof so that the new sheet metal of the transition would slip in behind it, making a nice clean joint. After I was satisfied, I removed the test piece, cut it, and dry fit it to check the joint. Then I reattached it temporarily so that the curved joint fit nicely. The test piece had to have enough material to pass over the top section of roof and beyond. I then turned my attention to the top curve. This one was easier as I could trace the front edge of the upper roof onto my test piece from underneath the transition while standing inside the bus. I made sure the piece was marked along its entire length then removed it once again and cut it. I dry fit it once more and made notes on it at the locations that would need adjusting on the final piece.
Once I get new steel for these transitions, I will lay my templates on the new metal, trace, make the changes I have marked, then cut them. Finally, I will weld them to the slanted framing members and caulk all the joints with high quality paintable caulking. I followed basically the same steps for the front transition except that I could trace both curves from underneath the sheet metal.
Next time: finishing up the exterior frame
