Interior roof panels for external use

[aswallie]

We're coming up on time to do our roof raise and I've started getting quotes from suppliers that just keep going up and up. A thought occurred to me and I called up a local bus scrap yard where the pull the mechanics and scrap the body and I got a quote for interior roof panels that seems much more reasonable. Thoughts on using them on the outside of the bus? I'm sure this has been covered a dozen times before and I'm sorry for asking it again but digging through old posts didn't find what I was looking for.

Bonus question, what the generally suggested/accepted overlap when doing a raise? From what I've seen a lot of people like to cut the window posts on a staggered pattern to reduce shearing points but as I understand welding if done properly there's no such thing. If that holds true the idea was to cut below the windows in as straight of a line as I could where I could use the top lip of the rub rail to cover the new skin.

[musigenesis]

The interior ceiling panels (sometimes called the headliner) are usually 20 ga. sheet, same as the roof and sides. However, 20 ga. is pretty floppy stuff, and it only achieves a semblance of stiffness because of the curvature on the roof and the rub rails on the sides. For covering the sides after a roof raise it might "oil can", bending in or out from the ribs, so it seems roof raisers usually go thicker.

Also, on many buses the headliner steel is perforated - make sure whatever you're getting from a scrap yard isn't that.

[aswallie]

Good point with it being on the floppy side and chances of an outward or inward bow, I'll need to weigh cost against the risk of that happening. The bus yard says of I pull the panels myself they'll changed me $15 a sheet so right now the price is every affordable. That also means I'll be able to avoid the preferred steel that the entire inside of my bus was lined with. I speculate the panels will be just over 32" by approximately 8'. If I raise it by 14" max that leaves me with 8"of extra material, if 2" above and below is enough overlap I could take the remaining 4" and bend a 90 into it then initial that inside the raise as an L channel of some sort to possibly mitigate the bowing.

Can anyone see a flaw in that process? Those with experience, is that not enough overlap?

[Mr4btTahoe]

I used my interior skins for window deletes and patch panels but I wouldn't use them for large areas. They are too thin unless planning on some extra bracing/framing.

[aswallie]

Would an additional rub rail in the mid outside area of the raise make enough of a difference to shore up the bowing? At most we'd go up 16 inches so there would be less than 8", probably closer to 6" worth of new thinner steel on it's own.

[o1marc]

Originally Posted by aswallie

We're coming up on time to do our roof raise and I've started getting quotes from suppliers that just keep going up and up. A thought occurred to me and I called up a local bus scrap yard where the pull the mechanics and scrap the body and I got a quote for interior roof panels that seems much more reasonable. Thoughts on using them on the outside of the bus? I'm sure this has been covered a dozen times before and I'm sorry for asking it again but digging through old posts didn't find what I was looking for.

Bonus question, what the generally suggested/accepted overlap when doing a raise? From what I've seen a lot of people like to cut the window posts on a staggered pattern to reduce shearing points but as I understand welding if done properly there's no such thing. If that holds true the idea was to cut below the windows in as straight of a line as I could where I could use the top lip of the rub rail to cover the new skin.

If you cut at the bottom of the windows, how to you access below the windows to weld the hat channel extentions? That's why the cuts are in the middle of the window. I deriveted the top row of rivets on the rub rail, drop the metal behind that and then rereivet the rub rail. You'll need to tack weld the tops of the new metal panels as there's nothing up there to secure it to. There is a rib every 24" or so, so oil canning is minimized if panels are secured with enough rivets. If you cut your 32" panels in half, that gives you 16" pieces. That gives you 2" of overlap at the base if tucked tight to the roof. Added Rub Rail may interfere with any windows you may plan.

[aswallie]

Originally Posted by o1marc

If you cut at the bottom of the windows, how to you access below the windows to weld the hat channel extentions? That's why the cuts are in the middle of the window. I deriveted the top row of rivets on the rub rail, drop the metal behind that and then rereivet the rub rail. You'll need to tack weld the tops of the new metal panels as there's nothing up there to secure it to.

Oh! That's a very good point that I hadn't thought about. Right now I'm looking to get my hands on the material and haven't finalized exactly how I want to do the raise but I'll definitely take this into mind when I do it. What's the best way to build the window frames if you cut at the windows?

[o1marc]

Originally Posted by aswallie

Oh! That's a very good point that I hadn't thought about. Right now I'm looking to get my hands on the material and haven't finalized exactly how I want to do the raise but I'll definitely take this into mind when I do it. What's the best way to build the window frames if you cut at the windows?

I misspoke, if you raise 14", you will need sheet metal 44" wide, it's 30" from roof to bottom of windows with a 2" overlap. So you would need it 14" wider. Once you have the roof raise determine where your windows will go and weld upper and lower horizontal bars between the ribs and then add bars on each side. Then reskin the outside, cut out your window holes and mount the windows.

[aswallie]

Originally Posted by o1marc

I misspoke, if you raise 14", you will need sheet metal 44" wide, it's 30" from roof to bottom of windows with a 2" overlap. So you would need it 14" wider. Once you have the roof raise determine where your windows will go and weld upper and lower horizontal bars between the ribs and then add bars on each side. Then reskin the outside, cut out your window holes and mount the windows.

I didn't specify entirely, I plan to use the existing stock windows possibly deleting up to 5 which I'm willing handle in a special case basis. That was part of the idea of cutting beneath the windows. The rough plan was to pull the windows, cut below, raise, rivet the outside skin as needed, then re-seal the old windows back in their existing spots.

I'm very open to cutting where the windows currently are but I'm not sure the best route on rebuilding the existing window "sills".