Putting the metal ceiling back up after insulating?

[Ronnie-SKO]

Would blocking the bus frame up help to limit the flex ?

parking on a hard level surface would be the best, if feeling energitic sure block it up.

 

[Warthog-SKO]

Why not just leave the metal up, and use "foam-in-place" insulation to fill the gaps between inner and outer metal "shells"??

 

[o1marc]

Why not just leave the metal up, and use "foam-in-place" insulation to fill the gaps between inner and outer metal "shells"??

Uneven expansion of the foam would warp the heck out of the panels, good luck fixing it after that.

 

[Warthog-SKO]

Why would the foam "expand unevenly"?? It is designed specifically not to do so, but to expand into open spaces preferentially.

 

[dgorila1-SKO]

OK, hear me out.

In my TC2000, we pulled out the metal ceiling and walls and spray foamed it all. Then we struggled for a while to come up with a good material to cover it all back up with. After a few attempts of various type we ended up with a beautiful tongue and groove wood plank ceiling that cost a lot of money and time.

With our new BBAA, I'm having trouble justifying that cash and effort outlay. This ceiling looks great, don't get me wrong, but I'm too practical (read: cheap) to do it again without exploring alternatives.

So the practical problems with metal ceilings basically come down to weight, thermal conductivity, and difficulty of putting it back up once you've taken it down.

Weight, well you got me there, it's heavy.

Thermal conductivity... Once I've taken the panels down, a 1.5 inch wide strip of rubber could be sandwiched between the ribs and the panels. Given the affected surface area, I think that could be a pretty darn effective thermal break even if it isn't perfect. Also using POM plastic rivets to re-attach the panels to the ribs so no metal to metal contact between the roof and the ceiling.

As far as putting it back up, I met a guy recently who was doing something similar and he had devised a jib to help hold panels up in place while he reattached them. Looked pretty good to me.

So that's my general idea. I've always liked the look of the factory bus ceiling, I just hated how much harder it is to keep the bus warm/cool when the weather outside isn't cooperating.

So brilliant idea or a fool's journey? What am I forgetting?

Am I missing something here? If you’ve already removed the original panels and installed tongue and groove, why are even concerned about this now? Are you asking because you’re doing another bus? If not it’s done and move on with the build.

 

[Ronnie-SKO]

He is doing another bus, first one had tongue and groove, now thinking of putting the metal back on the second one

 

[lemmeskoolu]

Can confirm. If you just want the look-and-feel of the original ceiling, and aren't a stickler for the metal panels (bus enthusiast, purist, want something to stick magnets to, whatever) you can use the 5mm underlayment panels from Home Depot. I think they're 13 bucks a sheet.

This is what we did. We ended up cutting each panel to be the width of the window, and they bent right into place. We covered the seam between panels with a 3" x 1/4" strip of wood, then painted the whole thing white. The result is that it sort of has the look of the original ceiling (a little better, as our original ceiling was perforated panels) without having to try and refit the original panels.
Just a thought.

Which panel exactly you used? And do you have a pic of that setup?

 

[dgorila1-SKO]

He is doing another bus, first one had tongue and groove, now thinking of putting the metal back on the second one

Ahh, now I see said the grasshopper to Mr. Miyagi!

 

[Drew Bru]

Which panel exactly you used? And do you have a pic of that setup?

This is the underlayment at HD. I didn't take any pictures when we were putting it up, but I made a crude diagram of a cross section of it, and a picture of the finished ceiling.

 

[EastCoastCB]

Why would the foam "expand unevenly"?? It is designed specifically not to do so, but to expand into open spaces preferentially.

Putting foam into a metal sandwich would be futile.

 

[o1marc]

Putting foam into a metal sandwich would be futile.

It isn't so much the uneven expansion as it is the inability to control the expansion, easily bowing/buckling the ceiling. How would you control full coverage in the cavity? I'm with Charlie on this, futile. Some mistakes are not worth the clean up results.

 

[kidharris]

Rubber has about the same thermal conductivity as wood, so you'd probably have an easier time bending (or piecing) a 2x2 to put over the rib - same thickness and you could use metal screws with countersinks to attach the wood to the rib, and then screws to attach the ceiling to these 2x2s, without creating any thermal bridging through the steel fasteners. And it would be relatively easy since you wouldn't need to line up any of the original rivet holes.

There's a "How It's Made" video on youtube showing my make of bus being built, and they show how the small black screws sticking out of the ribs near the tops of the windows is used to wedge the ceiling panel in place temporarily while they rivet (I had been wondering what those screws were for, because they just leave them in place afterwards and they're covered by the trim). You could just reuse those (or that technique) with maybe a simple 2x4 t-bar to help wedge it up in the middle.

I wouldn't do this myself ... thanks to the guys who stole my original ceiling panels.

You should realize that whether you use a rubber or wood spacer the sheet is going to come down further on the sides than original so centering it should probably be a priority so that the ends wind up looking the same on both sides (consider 2 concentric arcs/circles - the outer arc is longer so when you take the metal from the outer arc and put it in the inner arc the extra length will need to go down the 2 sides unless you trim the sheet). I like the idea of fastening the spacer to the ribs, then fastening the metal to the spacer. Sounds like it would be easier, more flexible, and still provide the thermal break. Much better than the plastic rivet idea. The rubber would match the curve better then wood, but will it hold a screw if you screw the metal to the rubber?


If the ribs are hat channel, then the foam is probably not inside of them, however there may be some fiberglass insulation inside of them from the factory. Personally I would find an adhesive/caulk for the thermal break (maybe glue a thin strip of rubber to the rib) and apply the metal over the adhesive/caulk/rubber and be done with it. The ribs are going to cause a weak place in the insulation no matter what you do. Anything separating the broad face of the hat channel making a metal to metal contact with the ceiling sheet is going to help.



It would be interesting to see a thermal image (FLIR?) comparison of different techniques to see what you actually get for all of the extra cost and work of different methods.

 

[kidharris]

I am not sure what they call them but aircraft use some form of temporary panel fastener that holds and aligns the panel. I imagine you used these on the C-130. I have seen them in use on aircraft during restoration. I do not know if they are "blind" or have to have access to the back side, but certainly worth checking out.

Cleco and they are "blind"

 

[kidharris]

Why? Literally any other material is better than the original metal ceilings. If you can't afford tongue and groove there's tons of cheap paneling types you can get at Home Depot or Lowes for 10 bucks a sheet.

I think that I prefer the additional strength that the original metal ceiling provides, some what like a box beam. This construction seems like a unibody mounted on a frame.





" Literally any other material is better than the original metal ceilings." Better for what?

 

[HappyInTN]

OK, hear me out.

In my TC2000, we pulled out the metal ceiling and walls and spray foamed it all. Then we struggled for a while to come up with a good material to cover it all back up with. After a few attempts of various type we ended up with a beautiful tongue and groove wood plank ceiling that cost a lot of money and time.

With our new BBAA, I'm having trouble justifying that cash and effort outlay. This ceiling looks great, don't get me wrong, but I'm too practical (read: cheap) to do it again without exploring alternatives.

So the practical problems with metal ceilings basically come down to weight, thermal conductivity, and difficulty of putting it back up once you've taken it down.

Weight, well you got me there, it's heavy.

Thermal conductivity... Once I've taken the panels down, a 1.5 inch wide strip of rubber could be sandwiched between the ribs and the panels. Given the affected surface area, I think that could be a pretty darn effective thermal break even if it isn't perfect. Also using POM plastic rivets to re-attach the panels to the ribs so no metal to metal contact between the roof and the ceiling.

As far as putting it back up, I met a guy recently who was doing something similar and he had devised a jib to help hold panels up in place while he reattached them. Looked pretty good to me.

So that's my general idea. I've always liked the look of the factory bus ceiling, I just hated how much harder it is to keep the bus warm/cool when the weather outside isn't cooperating.

So brilliant idea or a fool's journey? What am I forgetting?

If you get the DIY Berliner and roll that onto the hidden side, it'll help with rigidity and thermal conductivity. Good luck to you!

 

[kidharris]

Can confirm. If you just want the look-and-feel of the original ceiling, and aren't a stickler for the metal panels (bus enthusiast, purist, want something to stick magnets to, whatever) you can use the 5mm underlayment panels from Home Depot. I think they're 13 bucks a sheet.

This is what we did. We ended up cutting each panel to be the width of the window, and they bent right into place. We covered the seam between panels with a 3" x 1/4" strip of wood, then painted the whole thing white. The result is that it sort of has the look of the original ceiling (a little better, as our original ceiling was perforated panels) without having to try and refit the original panels.
Just a thought.

One interesting thing that I picked up from the "IC Bus on How It's Made" video is that the perforations helped with the sound control in the bus.

 

[EastCoastCB]

It isn't so much the uneven expansion as it is the inability to control the expansion, easily bowing/buckling the ceiling. How would you control full coverage in the cavity? I'm with Charlie on this, futile. Some mistakes are not worth the clean up results.

Even if it went in and cured perfectly- what's the point of it? Foam between layers of steel?!

 

[EastCoastCB]

One interesting thing that I picked up from the "IC Bus on How It's Made" video is that the perforations helped with the sound control in the bus.

It cuts down on the echoing a little bit.

 

[EastCoastCB]

I think that I prefer the additional strength that the original metal ceiling provides, some what like a box beam. This construction seems like a unibody mounted on a frame.





" Literally any other material is better than the original metal ceilings." Better for what?

Buses are not unibody. They're body on frame.

Have you ever driven one without the metal headliner?

If its structural its pretty minimal.

Ever seen a high end motorhome with a metal headliner? ever?

 

[Ronnie-SKO]

Buses are not unibody. They're body on frame.

Have you ever driven one without the metal headliner?

If its structural its pretty minimal.

Ever seen a high end motorhome with a metal headliner? ever?

I think what Kidharris is saying is the body is built as a complete unit able in it's self to hold up in an accident, hence "unibody". He does say mounted on a frame, the bus chassis. Considering that the body is meant to slide on the chassis in a head on collision, this makes sense. It may not be the best choice of words however not sure how to say it better.

In a roll over a bus stays in one piece, in a roll over a motorhome gets flattened. I am sure that removing the metal ceiling will have little or no effect for normal driving. However in a roll over then it does come into play as a structeral member. I hope to never roll over. However one of the reasons I want a bus and not motorhome is strength, and durability.