Roof Choppy vs Integrity

[Joe45]

So I've been thinking about chopping off the front roof of the bus to just behind the driver seat/cockpit area, lowering it to a few inches above seating head height (like a Class C or Super C), reinforcing it with a 1/8 tubular steel frame riveted and welded to the body, with a sheet of 1/16" steel plate as the ceiling.

I would run 20' one piece steel tubing from the front to the back, tying them, and the loft/overhang section, into the roof deck and bus superstructure with rivets, welds, bolts...

This would allow me to build a loft for sleeping above, with a Class C/Super C style overhang above the hood. Cutting the roof there would give me a foot+ extra vertical space for the loft, so raising the loft 3 feet over the bus roof, plus the additional foot plus below would be good headroom with a mattress.


Any ideas and/or opinions?



Here's what I am thinking of:

 

[Frogpondfoug]

That's bunch of work for somthing that probably be either floppy or compermize the rest. It's a bus not a skyscraper hope this helps

 

[Joe45]

That's bunch of work for somthing that probably be either floppy or compermize the rest. It's a bus not a skyscraper hope this helps

I don't see why it would be floppy if it is welded and bolted to the body. Also, it would rise 3' over the current roof. Plenty of people do a roof raise that approaches that.


Not sure it it will be worth it, but seems like it would be a good way to get 4' of room for the sleeping loft area.

 

[Joe45]

I'm very sad that no one else has chimed in. :ermm:

 

[Danjo-SKO]

It’s a good idea. What’s the ratio of cantilever? In architecture 3:1 is considered the maximum IIRC.

And why would it be floppy? When I was a kid I would ride on the bed it was great. Those cabovers are made of sticks and tin cans

 

[Joe45]

It’s a good idea. What’s the ratio of cantilever? In architecture 3:1 is considered the maximum IIRC.

And why would it be floppy? When I was a kid I would ride on the bed it was great. Those cabovers are made of sticks and tin cans

Thanks!


I have no idea of ratio to cantilever, or how to come about this calculation. Nor do I know what "IIRC" is. If you have an easy, non-engineer method of determining this, I'll give the calculation a try.



I was thinking the same thing about the "floppyness". It's all steel. My idea would be not only to run a length of 1/8x2" angle across-above the window-riveted/bolted on for reinforcement, but also 1.5x1.5x1/8 wall (or the angle as before) into the bus, lengthwise, and attached with bolt, rivets, and/or welds to the roof framing. It would then have a steel frame on top, with the steel tubing as part of the deck and running at least 15 feet back before needing another piece. Then it would be skinned with something like 18 gauge steel sheet. I can't see that being floppy.


I've even thought of fabricating an internal roll cage for the cockpit, and havin it welded by a pro. But this could be overkill.

 

[Danjo-SKO]

Maybe a more complete drawing would help.

IIRC = If I Recall Correctly

 

[Joe45]

Oh I see!


I'll see about putting up a better drawing.

 

[Native-SKO]

I like that you think out of the box, Joe!

 

[joeblack5]

That is a nice design. You are creating floor space without changing the bus length.
I would set the front standing members / studs right on top of the A pillar so that the down forces are directly supported. Depending on your overhang and weight you want to construct as light as possible . remember that static weight forces will be easily amplified a factor 4 depending on what depth pothole and speed .

If you go cheap and use bed frames then remember that it is carbon steel that needs an knowledgeable welder to avoid cracking in the weld area.

Good luck. Nice design.. Johan

 

[Joe45]

I like that you think out of the box, Joe!

Thank you!

 

[Joe45]

That is a nice design. You are creating floor space without changing the bus length.
I would set the front standing members / studs right on top of the A pillar so that the down forces are directly supported. Depending on your overhang and weight you want to construct as light as possible . remember that static weight forces will be easily amplified a factor 4 depending on what depth pothole and speed .

If you go cheap and use bed frames then remember that it is carbon steel that needs an knowledgeable welder to avoid cracking in the weld area.

Good luck. Nice design.. Johan

Thanks!
The plan is to use steel tubing and/or angle. Thinking 1/16 wall. Skinning it with 18 gauge (or approximate) steel sheet.



I didn't know bed frames were carbon steel. Now that I think of it-that's probably why they're so damned difficult to drill into!


I've been thinking of reinforcement plates at corners-maybe riveted-to give a little extra strength.


It's 7:46AM here and 41 degrees. It'll climb to the mid 70s by noon-but winter is approaching. Wondering if welding if it gets colder will be an issue. Maybe I'll have to heat up the metal.


Anyway, I'll see about putting up a better drawing asap.



Thanks again!

 

[johnsmithx1974]

Take pics! I'd love to know if it works out! Saw a pic of a bus top, on top of a bus...yours sounds more professional

 

[Joe45]

Take pics! I'd love to know if it works out! Saw a pic of a bus top, on top of a bus...yours sounds more professional

Yeah, I've seen similar pictures: of a VW van, and also of another school bus on top of a bus. I did consider both, but the VW looks too hippy/wierdo/half-assed, and the school bus on top just seem like a pain to cut it exactly right, then lift it up there, etc. I figured building it onto the bus would look better, be easier, and also be stronger.


I have my bus build videos on my youtube channel. Four uploaded so far, and about five more that need to be edited. I will surely film the loft making!

 

[gs1949]

I just noticed this thread. I think this is a very good idea, but I wonder if it might be better to use heavier tubular steel. I have a known tendency to over-build things, but my instincts tell me that it might not be too difficult to overload that eighth-inch tubular when it's cantilevered like that.
If there will only ever be children up there, that's obviously strong enough. But the question is how well it would hold up with a couple of heavy adults. I think this way in part because I am still fairly heavy myself, just not as heavy as I used to be.

 

[JustKip]

I really don't see an issue with it at all. I've seen pics of a vintage, dog-nose style bus, with the "cab-over camper" style bedroom extending all the way to support columns coming up from the front bumper brackets.

 

[Free Bird-SKO]

So I've been thinking about chopping off the front roof of the bus to just behind the driver seat/cockpit area, lowering it to a few inches above seating head height (like a Class C or Super C), reinforcing it with a 1/8 tubular steel frame riveted and welded to the body, with a sheet of 1/16" steel plate as the ceiling.

I would run 20' one piece steel tubing from the front to the back, tying them, and the loft/overhang section, into the roof deck and bus superstructure with rivets, welds, bolts...

This would allow me to build a loft for sleeping above, with a Class C/Super C style overhang above the hood. Cutting the roof there would give me a foot+ extra vertical space for the loft, so raising the loft 3 feet over the bus roof, plus the additional foot plus below would be good headroom with a mattress.


Any ideas and/or opinions?



Here's what I am thinking of:
View attachment 37497

I spose most of us have wished for a loft bed up there at one time or another. I won't be doin it as I don't want to be any taller and I'm much too lazy.
My thoughts on yer plan are somewhat disorderly but here they go.

With the arched roof gone you definitely don't want to get this baby upside down.

I'm assuming this structure is boxy like a camper? if so the strength of the sidewall sheathing (inside and out) if run back past the cantilever point could be enough to support the overhang?

Your talking 1x1 I/8 wall square tubing? Probly deeper for the cross pieces, they are runnin close to 8' unsupported and no arch

Maybe 3' overhang?

Where ya might run into a snag is visibility, regular Class C's don't extend much past the windshield and you need a good view of stop lights at intersections. That's not a deal breaker though cause you can move the whole unit back until it works and maybe get better aerodynamics to boot.

Might want a hinged or slidy section for the head banging area where you come in the door.

Stick a sign in the loft sayin "NO AGGRESSIVE COUPLING BEYOND THIS POINT!" "ESPECIALLY WHEN I'M DRIVIN THROUGH POTHOLES!" "THIS MEANS YOU" "YA, ALL THREE OF YOU"!!!

Seriously if ya don't do this you're whole project could be jeopardised by too much f---ing overhead.

 

[Joe45]

I have considered raising the roof in that section. Have also considered a roll cage for that section as well. I am concerned about safety due to this. Don't want to make it unsafe.



Since the overhang will be about three feet, most of our weight would be on the inside part, with the steel crossbeam over the window about right in the middle.



I'm thinking 1.5x1.5x1/8 or 2x2x1/8


Might run support beams down as well.



I don't want to make it so heavy that the weight/mass compromises the cockpit.


I would put padding for the cranium.


As far as fun upstairs-that will be my wife and I, so no driving while there's fun-at least not like that.

 

[Joe45]

Here's an idea:


To retain safety, does anyone think that raising the roof in that section of the bus is a good idea? I mean, to keep the curve of the roof?


Or maybe make the roof from scratch, with a curved top?


Or is this whole idea too risky?



I don't want to compromise safety and turn the bus into a collapsing metal trap.

 

[o1marc]

I'm trying to picture the speed you need to roll a bus on it's roof. I think too much thought is put into this. How many members have ever rolled a bus on it's side, let alone onto it's roof. My theory that these are so over built was cemented when I learned that the Wander Lodge by Blue Bird has half the ribs as in the school bus, don't ever hear of those crushing in a rollover. Replacing the curved roof with a square edged one would seriously compromise crash stability.