Is there a standardized height or heights for a roof raise?

[bridg73988]

Is there a standardized height for a roof raise? Has anybody that has been part of a roof raise project hit a point where they said "Oh crap, if I had known that I would have done a X inch lift instead". For example, I plan on converting to double pane insulated RV windows, are those standard sizes. If so should I plan my new roof height around those measurements or is it better to just raise the roof then frame in whatever windows I find or want? I don't want or need a huge raise but if I am going to do it I need it to be worth it and also visually appealing.

 

[M1031A1]

So long as your outside dimensions do NOT exceed 13' 6" from roadway to the highest point of the bus anything goes. IF you exceed that height then you are looking at an over-sized vehicle that can NOT go under most bridges AND may need permits to be driven.

Roof raiser beware.......

Just sayin'.....

M

 

[EastCoastCB]

Is there a standardized height for a roof raise? Has anybody that has been part of a roof raise project hit a point where they said "Oh crap, if I had known that I would have done a X inch lift instead". For example, I plan on converting to double pane insulated RV windows, are those standard sizes. If so should I plan my new roof height around those measurements or is it better to just raise the roof then frame in whatever windows I find or want? I don't want or need a huge raise but if I am going to do it I need it to be worth it and also visually appealing.

I raised mine ten inches. We could have went higher or lower. We just raised till I thought it looked and felt right.
And yeah RV windows come in a wide array of sizes.

 

[Rusty-SKO]

Dare to be different...

I think roof raise is over-done. Maybe time for something fresh?

 

[bridg73988]

Definitely not looking to go as high as possible. I am 6' tall with a bus that is 6'6" at the peak inside. By the time I redo the floor with insulation, plywood, and finish flooring I will lose a few inches. Then, insulating the roof and putting tongue and groove boards on the ceiling will cost me another 1-2 inches. When I am done I will barely be able to stand up straight in the middle of the bus. I don't want to go through the massive undertaking of a roof raise but I would like to be able to stand up without bumping my head on the roof. Also the shower is along the side of the bus so I would be ducking down everytime I take a shower. Seems as though a raise is inevitable, so back to the decision of how high. I don't want to do all the work for 6 inches just to find out that a lot of standard sized items would have worked if I had just gone 10 inches instead, or vise versa. So here I am, asking for the wisdom of experience from those that have "been there, done that, wish I could have a do over" to prove it. So with that, I welcome anybody's input as to how high they raised, what worked and what didn't, and what they liked or would change if they could about their roof raises. Thanks.

PS - like the slammed pics, I have seen an old bus shortened and slammed at a car show before!

 

[1olfart]

That Crown really lights my fire!
If I had the skills, and wanted a full size bus, I would have already bought the Crown in last weeks post. (It might take a while for me to get the $, but I would)

AS for the roof....IMO.... no limits. Find your 'Happy spot" and go for it.

 

[Nomadiana]

Dumb newbie questions

Okay, so I have a few questions:

1. Why do people raise the roof on a bus? Just for added headroom?
   
   
2. Wouldn't a higher roof potentially change the bus's center of gravity and/or make it more top-heavy, especially with cabinets built high inside or a solar array up top?
   
   
3. Wouldn't buses with raised roofs be more susceptible to twisting or shearing in high winds and, I suppose, less aerodynamic?
   
   
4. Since buses have steps that take you up to a higher floor, wouldn't it also be possible to lower the floor during the process of tearing it out and adding insulation, which would keep the center of gravity low?

 

[Rusty-SKO]

1) yes
2) yes
3) yes- aerodynamics of a brick.
4) no- frame is in the way.

 

[bridg73988]

1. Yes
2. Yes, but I only want to add a few inches (which is my dilemma, lot of work for very little yet necessary gain)
3. Yes, brick either way
4. No, frame as Rusty stated

 

[Nomadiana]

1) yes
2) yes
3) yes- aerodynamics of a brick.
4) no- frame is in the way.

1. Yes
2. Yes, but I only want to add a few inches (which is my dilemma, lot of work for very little yet necessary gain)
3. Yes, brick either way
4. No, frame as Rusty stated

Thanks for your quick replies! I had a feeling aerodynamics was not a large concern with buses. For me, not being a confident driver, it seems the most important aspect of raising a roof is the center of gravity issue. But is it that buses are heavy enough that it doesn't really matter?

Also Re #4 - when you say "frame" is that different from a chassis? So, the frame sits on top of the chassis??

I am thinking of some smaller RVs, such as the Tiger, which is built down low on top of the chassis of a cutaway truck. A bus body goes down low on the outside but has a raised floor inside due to its frame, is that it?

Is raising the roof is better for longer buses than for shorties? I'm picturing a high shorty not handling well enough to avoid toppling over. Am I totally wrong?

 

[PNW_Steve]

Picture the body as a box sitting on top of two frame rails then add "skirting" around the sides to hide the ugly frame.

 

[bridg73988]

Yes, on my bus as with almost all school busses, the actual frame rails that run from the front to the back are directly under the floor that you walk on inside the bus. Mine has storage underneath that actually goes under the frame of the bus. As for high center of gravity, yes, a 24 inch raise with lots of cabinets and overhead storage and rooftop a/c units and a bunch of solar panels or a giant metal rooftop deck/porch could significantly alter the center of gravity. My plan was just enough of a raise to be able to move around without having to duck down. And as for cabinets, I don't have plans for many. And I won't have anything on the roof except MAYBE some solar in the future. So, I won't be adding much in the way of weight on the top end.

 

[Rusty-SKO]

Think truck ladder frame with a "box" set on top. Now add side skirts to hide frame.

 

[EastCoastCB]

Okay, so I have a few questions:

1. Why do people raise the roof on a bus? Just for added headroom?
   
   
2. Wouldn't a higher roof potentially change the bus's center of gravity and/or make it more top-heavy, especially with cabinets built high inside or a solar array up top?
   
   
3. Wouldn't buses with raised roofs be more susceptible to twisting or shearing in high winds and, I suppose, less aerodynamic?
   
   
4. Since buses have steps that take you up to a higher floor, wouldn't it also be possible to lower the floor during the process of tearing it out and adding insulation, which would keep the center of gravity low?

1- because folks like me don't wana spend time in a cramped, crowded tin can. Adding ten inches of headroom made ALL THE DIFFERENCE. I'd do it again in a heartbeat. The bus feels AMAZING now. Before it was claustrophobic.

2- If you raise it dramatically, yeah probably. I've driven mine around after the raise and it feels exactly the same. Coach folks have been raising roofs for decades with no real ill effects. The roof of a bus is surprisingly light. The weight is going to be MORE than offset by the addition of black, gray, and freshwater tanks as well as a big honkin generator.

3- I did a proper job of making mine strong, so absolutely no twisting to speak of. Been off roading a bit in it afterwards, even. Mine is probably stronger than stock. Winds I can't comment on, but its already a giant brick, I highly doubt ten inches makes much of a difference.

4- lowering the floor would require such a serious amount of re-engineering and crazy fabrication that its totally not even worth thinking about, IMO.

A lot of folks have no business raising their roof. Lots of hack jobs, for sure. But if you do it right its by FAR the greatest mod you can make to create a REAL livable space.
Another thing- my bus only came with just over six feet of headroom. The factory built taller buses with up to 6'6" headroom. So really I've only went four inches or so higher than the factory was building them. For me it was stupid NOT to go for it. Best thing I've ever done, ever!

 

[EastCoastCB]

Yes, on my bus as with almost all school busses, the actual frame rails that run from the front to the back are directly under the floor that you walk on inside the bus. Mine has storage underneath that actually goes under the frame of the bus. As for high center of gravity, yes, a 24 inch raise with lots of cabinets and overhead storage and rooftop a/c units and a bunch of solar panels or a giant metal rooftop deck/porch could significantly alter the center of gravity. My plan was just enough of a raise to be able to move around without having to duck down. And as for cabinets, I don't have plans for many. And I won't have anything on the roof except MAYBE some solar in the future. So, I won't be adding much in the way of weight on the top end.

Sounds like my kind of plan! GO FOR IT!!!

 

[Nomadiana]

Another thing- my bus only came with just over six feet of headroom. The factory built taller buses with up to 6'6" headroom. So really I've only went four inches or so higher than the factory was building them.

Interesting! What is the overall exterior height of your bus now?

Also Re #4 - when you say "frame" is that different from a chassis? So, the frame sits on top of the chassis??

Picture the body as a box sitting on top of two frame rails then add "skirting" around the sides to hide the ugly frame.

Think truck ladder frame with a "box" set on top. Now add side skirts to hide frame.

Okay. Well, I don't know anything about truck frames, and I'm not sure if I was looking at the right spot in the pic but, obviously, a ladder frame has rungs like a ladder. What I am still NOT clear on is whether or not the words "frame" and "chassis" are interchangeable and referring to the same structure. Or does a vehicle have a chassis upon which a certain type of frame rests, meaning that a frame and chassis two different things? Does the type of frame determine how high someone can go with raising the roof, or does it just affect what can be done with the floor?

 

[Nomadiana]

The roof of a bus is surprisingly light. The weight is going to be MORE than offset by the addition of black, gray, and freshwater tanks as well as a big honkin generator.

What if someone wanted their bus build to be very simple, without a generator, plumbing, and black and gray tanks? Would that mean they should not raise the roof?

 

[Brad_SwiftFur]

Okay. Well, I don't know anything about truck frames, and I'm not sure if I was looking at the right spot in the pic but, obviously, a ladder frame has rungs like a ladder. What I am still NOT clear on is whether or not the words "frame" and "chassis" are interchangeable and referring to the same structure. Or does a vehicle have a chassis upon which a certain type of frame rests, meaning that a frame and chassis two different things? Does the type of frame determine how high someone can go with raising the roof, or does it just affect what can be done with the floor?

Frame generally refers to the ladder-like structure upon which pretty much everything else is attached. Many *DO* have cross-members which are very similar to the rungs of a ladder.

Chassis usually refers the the frame, springs, axles (both of them), wiring, fuel and brake lines, fuel tank, engine, transmission, radiator, and drive-line as a complete assembly. It may also include the hood and firewall, for some models. Basically, an almost-ready-to-drive vehicle sub-assembly.

Many modern cars do not have full length frames any more, they are "unibody" construction. Pickups mostly still have frames as do medium duty and heavy duty trucks and many (not all) buses.

A roof raise is probably the easiest and most effective way to increase headroom in a school bus, as the floor will be very difficult to lower. A *LOT* of engineering went into how they are designed and built, and the walls rest upon the floor (thus, lowering the floor will end up lowering the walls anyway). If I were to raise my roof, it actually doesn't look all that hard ... just time consuming.

 

[EastCoastCB]

What if someone wanted their bus build to be very simple, without a generator, plumbing, and black and gray tanks? Would that mean they should not raise the roof?

The furniture, personal belongings, people, dogs, etc will more than offset that weight, then. Use your imagination lol. Even if the weight isn't offset, its not enough to be concerned about unless you do crazy stuff like mounting big heavy stuff on top of a 24" raise.

 

[Tango-SKO]

Wind loading from the sides is typically a bigger issue than CG.