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-   -   How much does a roof weigh? (https://www.skoolie.net/forums/f13/how-much-does-a-roof-weigh-36333.html)

MadCompSci 06-09-2021 06:28 PM

How much does a roof weigh?
 
I know - it depends. So here's some specifics:
2004 Thomas front engine flat nose, about 40' long tip to tail.
Cut from just behind the driver's seat, along the windows, and above the rear door.

2500 pounds?

rossvtaylor 06-09-2021 06:45 PM

I have not weighed one...but I don't think it's anything near that. You hardly need the jacks to lift one end...

I'll be curious to see what the actual numbers are, from someone who's used a scale. Following.

ewo1 06-09-2021 07:27 PM

Quote:

Originally Posted by MadCompSci (Post 441717)
I know - it depends. So here's some specifics:
2004 Thomas front engine flat nose, about 40' long tip to tail.
Cut from just behind the driver's seat, along the windows, and above the rear door.

2500 pounds?

Way too much…!

Figure out how much 1 piece of 4x10 18ga sheet metal weighs… I’m gonna guess it at 50 lbs, probably less though but, multiply that by say 10 sheets?

That will get you to around 500 lbs. then there the hat channels, add another 100 lbs?

I’m really guessing wild here!

Danjo 06-09-2021 07:39 PM

Mmm never mind

Danjo 06-09-2021 07:45 PM

Per window?

18” raise

3 pounds per sq ft

4.5 pounds per linear foot

10 pounds per window

That seems like not enough

musigenesis 06-09-2021 07:50 PM

I did a calculation a while back and came up with about 750 pounds for my roof (11-window International CE 300), not counting the removed headliner. 16 ga. steel sheet is 2.5 pounds per square foot, and the roof is about 8' x 27.5" inches per window, or about 18 square feet per window. So my 11-window bus has about 202 square feet of sheet for about 500 pounds. The rear cap plus the cab area is maybe another 50 square feet and 125 pounds (625 total).

The hat channel ribs are equivalent in material to 1.5" square tube with 16 ga. walls, which is about 1.25 pounds per foot, so each 8' section of rib is about 10 pounds; with 13 ribs that's another 130 pounds, or about 750 pounds total for my roof (I don't think the rivets are a whole lot, maybe another 10 pounds or so). The two longitudinal stringers are maybe another 50 pounds and the hatches don't weigh much at all, so maybe 800 pounds is a better estimate. A 40-footer RE or FE would probably be closer to 1000 pounds (or maybe a little over that).

Edit: whoops, I screwed up - my roof is 20 ga. (1.5 pounds per square foot) not 16 ga., so my roof would be more like 600 pounds than 800. Pretty remarkable that something this light is as strong as it is, but it shows that the shape of the material is a lot more important than the amount of it.

Simplicity 06-09-2021 08:54 PM

I'm assuming you're doing a roof raise.

Weight is a factor, but as Ross already stated, a small hydraulic jack will be able to lift it.

I think more important is the sail affect and the awkward affect.

Take one of those 54"w x 8' long ceiling panels, pick it up with a bit of a breeze and try carrying it. Multiply that to create a 40' x 8' sail.

I've never seen how a roof has been raised. I'm sure there are some engineers and some more redneck designs, all of which most likely worked just fine.

I'd think attaching slide posts to the floor at least every other roof rib. Then, slip a slide piece over the post and then weld the slide piece to the roof rib. This will allow you to raise the roof and keep it somewhat secured as it raises.

Good luck!


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