Reskinning bus after roof raise ... question about measuring.

[Brewerbob]

So, all of my interior skins are down and I'm ready to measure for new skins. If you've done a roof raise or seen a roof raise, please let me know how to measure.

On my bus, I have 8 feet on center from what would be the A pillar to the window behind the driver's seat. This is where the convenient stops. The rear is 7 feet on center to a rib. Now for the real questions... I'm thinking I want to alternate the skin from one side to the other. Use a single sheet to the 8 feet on port and then use a 10~12 foot sheet and go to the next rib on starboard or something like that. The door is 40" so I could stagger using it. Thereafter all of the ribs are 25 or 32 inch on center. Nothing remotely standard for sheet metal.

Next question is about overlapping. The ribs are a C channel like below... They measure at least 2 inches from edge to edge. I think they measure closer to 3 inches actually with A, B, and C all being roughly 1 inch each. Is that enough overlap? So, for the red sheet I should, "shingle" it as in 1 or alternately "stack" them like 2? I don't remember how the bus is put together OEM. I'll have to remember to look at that this afternoon. As long as C and D are 5 feet apart the "crooked" sheets of 1 won't be too noticeable.

 

[mmoore6856]

started cutting my roof yesterday im using 4'x10' sheets and covering all windows going to take first row of rivets out above windows and tuck my steel in and drill the same holes and use carriage bolts #12 x 1/2 as far as the bottom im welding it on the inside im doing a 20" raise from just behind the drivers seat and add a taper up there as a flat collects lots of bugs

 

[Brewerbob]

started cutting my roof yesterday im using 4'x10' sheets and covering all windows going to take first row of rivets out above windows and tuck my steel in and drill the same holes and use carriage bolts #12 x 1/2 as far as the bottom im welding it on the inside im doing a 20" raise from just behind the drivers seat and add a taper up there as a flat collects lots of bugs

4'x10' doesn't line up pretty with the ribs on my bus.

What's your overall height going to be? I want to keep mine under 12'. I'm currently at 10' even at the top of the beacon. I'm also thinking about "raising" the floor. Have 8~12" under floor storage. I know a 4' sheet with 3" top and bottom overlap will give me an 18" raise (covering the windows entirely). If I split the raise between floor and ceiling... Or if I need less than 3" overlap top and bottom... then I'll have more I can split.

I do want the new metal under the rub rail but I don't know if I need it under both sets of rivets or just one.

 

[Tango-SKO]

10' sections are handy to work with in one way but very difficult to place and secure properly without a lot of oil canning. Make sure they stay warm/hot enough to elongate a little as you apply.

 

[Rusty-SKO]

Next question is about overlapping. The ribs are a C channel like below... They measure at least 2 inches from edge to edge. I think they measure closer to 3 inches actually with A, B, and C all being roughly 1 inch each. Is that enough overlap? So, for the red sheet I should, "shingle" it as in 1 or alternately "stack" them like 2? I don't remember how the bus is put together OEM. I'll have to remember to look at that this afternoon. As long as C and D are 5 feet apart the "crooked" sheets of 1 won't be too noticeable.

My bus came with no side windows at all and they lapped the sheets. You want to lap from top-down and front to back to keep water infiltration to a minimum at seams. Think cedar shake roof.

 

[Brewerbob]

My bus came with no side windows at all and they lapped the sheets. You want to lap from top-down and front to back to keep water infiltration to a minimum at seams. Think cedar shake roof.

Makes sense but I wasn't even thinking about it at 60mph thru the rain. Good point.

 

[Brewerbob]

Make sure they stay warm/hot enough to elongate a little as you apply.

That might be a problem.... especially if I wait until Oct.

 

[family wagon]

I've just finished hanging the big pieces on my bus. They're shingle-lapped as in your drawing 1 and in Rusty's description so that water falling down or blowing rearward while driving doesn't easily find its way in. The storage bin frames went on first, then the panel over the engine, then each panel working forward on the bottom row (about 39" tall). Next the upper panel at the rear, and again working forward to the windshield (48" wide panels). I didn't really like having it four plies thick at the five points where two upper and two lower sheets came together, but it is what it is. The stack-up could have been limited to three plies by staggering the upper and lower courses.

We took advantage of the hotter-than-usual July here and worked in full afternoon sun about 1 pm to maybe 7 pm on days when the forecast was for highs of 95° F or higher in hopes that the panels would expand under the solar heat. Hopefully that'll be adequate to prevent oil-canning later under the heat of spray foam or future summer sunshine.

On my bus, which is a Blue Bird but has the hat channels spaced differently than the school bus bodies do, the left side worked out as follows. Rear-most is 120" long and just covers the rear flange of a hat channel, up to the rear flange of another hat channel 10 feet forward. Second panel does the same. The third panel was cut a bit shorter; I don't recall its length. The fourth was cut down to about 101" length.

 

[cadillackid]

That might be a problem.... especially if I wait until Oct.

if you spray them with black primer and work on sunny days, you should have them be plenty warm in october.
-Christopher

 

[Brewerbob]

pics

Good grief!!! Did you buy just a frame and engine? Luckily I'm not doing that much.

Rear-most is 120" long and just covers the rear flange of a hat channel, up to the rear flange of another hat channel 10 feet forward. Second panel does the same. The third panel was cut a bit shorter; I don't recall its length. The fourth was cut down to about 101" length.

Nice. I don't think mine is going to be close to that. Below are the ribs. I dunno if I believe my own note about the first gap. I want to say the passenger door and driver window are 40" to cover the entire ribs (not center to center).

Front to rear starting at the windshield 35" 28" 28" (I think this is where I measured 8 feet) 35" 35" 35" 28" 28" 35" 28" 28" 28" 28" 28" 28"​

 

[Brewerbob]

if you spray them with black primer and work on sunny days, you should have them be plenty warm in october.
-Christopher

It won't oil can and I don't have access anyway but does anyone worry about the opposite; black and Phoenix 122°?