What to do with the Back Wall skins

[Tyania]

So I see a lot of people insulate the walls out to the end of the metal lip along the lower walls and insulate and build off the back wall panel/skin until it squares with the side wall... or don't insulate the back wall at all.
But.....
I am spray foaming the walls only an inch and a half off the wall (to where the original panel was). Yes, I am a stingy inch pincher. The back wall conducts heat terribly and I would like to remove that inner metal skin, foam insulate, and replace the skin with something other than metal. Also I would like to get rid of that upper area of the back wall where the flashers and sign are enclosed.

Problems/doubts:
1) Of course that means deleting the windows since the metal skin was molded to hold the window. But I can live with that unless someone has a solution.
2) CAN those back panel skins be removed? I see some spot welding where the side was rail goes over it and where the light box meets it.
3) Are any of these skins and framing structural?

And of course:
Is there an easier, more efficient way to stop the heat conduction without giving up much space?
I have seen a thin insulation over the skin and then a bendy board over that. But I can´t get the light box apart without taking off the wall skin.

 

[Robin97396]

Removing the interior skins is one of our favorite pet peaves. Most remove them, but some don't as a personal preference or because they live in agreeable climates.

It's interesting how you're on the other end of the heat scale, compared to us northerners. It's getting cold right about now. There was frost on the pumpkin this morning.

There is a current discussion on another thread, mostly about alternative types of insulation.

To answer your question, we don't consider the interior panels to be structural but the bus makes do consider them to be structural. This includes the end panels. Yeah, get the metal out so it doesn't conduct heat. And yes we insulate the end panels. Those metal end panels are pretty good to use as patterns when you're replacing the interior surfaces with whatever materials you choose.

The interior window skins on the back wall don't hold the windows in place. The windows are mounted to the exterior skin as far as I aware.

On the side walls beneath the windows we usually remove the panels down to the level of the rail that the seats bolted to, about 10" from the floor. We don't take out the lowest portion of the panel that meets the floor or the seat rail that is tack welded in place. The foam can be sprayed down into the pocket between the inner and outer skins in that area. The seat rail is considered structural from what I've been told.

It sounds like you're moving along with your build. In extreme heat like you're talking about, some people have made roof panels that sit above the roof like on a range rover. It keeps the sun from directly hitting your metal roof.

 

[Tyania]

Thank you Robin.

Anyone know of an example of the back skin removal in photo or video. Everyone loves to show how they get the side wall panels off but, I haven't found a single one of the rear skin in particular after weeks of searching. I suppose if it has been done, than I should just start hacking at it with confidence but...

I see one complication for starters just looking at it. The rear skin goes behind the side rail panel (the one that can't be removed), is under the first set of rivets through that rail panel, and is spot welded to the rail panel. See the first photo of my opening post. Would I have to cut around that spot and remove the back skin minus that square?

The other obvious option is insulating and paneling within the skin. But the most I would be willing to do in my effort to save space is to put a quarter inch insulation sheet with an eighth inch panel over it. Would that make much difference? It would provide a thermal break but not much in the way of insulation. Not to mention might not be the most attractive option. Opinions?

 

[Tyania]

There is a current discussion on another thread, mostly about alternative types of insulation.

In extreme heat like you're talking about, some people have made roof panels that sit above the roof like on a range rover. It keeps the sun from directly hitting your metal roof.

Any chance that you know which insulation thread addresses the back skin that you mentioned? There are sooooo many and I haven't found direct mention of the rear skin removal.

I tried looking up what you meant about the range rover... I plan on putting a roof rack (half dec and half solar panels) which should help shade the bus. Is that similar to the idea you were referring to?

 

[Jolly Roger bus 223]

Anything you can add on to help shade or cover the roof to block it from direct sun will help.
For the rear wall part I can't help you with removal except just cut it out?
But I do have a few alternatives.
Instead of removing the panel's for spray foam? There is a product out there made buy (therma corp. I think) that is a pour in compound/mixture that turns into the expandable foam as it cures. At my work we use it for underground piping systems. So it is compatible with steel,copper,PVC..
We get it in minimum gallon jugs and even 55-gallon drums and we call it A and B compound where you mix (example 6- ounces of part A to 6-ounces of part in a popcorn cup and pour it into the hole in the wall opening.
Then you only have about 15 -seconds after you pour it in on a hot day before it is foaming back at you and you cover the hole and let it expand.
Good stuff and I have even insulated 1200 degree steam piping like that.
After that then you could put thin insulation and a board over that.
And or I plan on doing a 3' wides x bus width back porch with a roof that matches the bus body the same width out.
That would also provide some shade on the bus panels on the back?
Good luck.

 

[Robin97396]

Sorry, I had to leave my mountain retreat and go to town to get another 44# bag of cat food.

There is little mention of removing the back wall panels, I think, because each of us spent an rediculous amount of time doing it. Just removing the interior skins from the back wall took me about a day and a half. Not something I'm proud of, so I assume it's the same for the others.

All mentions of panel removal I've heard in the past two years were very brief and unhappy. The lower panels seemed to be tied into the floor and frequently had to be removed using a grinder at floor level. If there's a rear heater against the wall it certainly needs to be detached from the wall to get the panels off. I tried leaving my heater connected to the hoses and wires, but it had to go to get that back panel out.

 

[EastCoastCB]

Robin- are you talking about removing the chair rails??

 

[Robin97396]

Absolutely not. That's structural as far as I'm concerned. My older buses do have a bolt on chair rail that's still there too.

No, OP is asking about the panels on the rear wall.

 

[EastCoastCB]

Absolutely not. That's structural as far as I'm concerned. My older buses do have a bolt on chair rail that's still there too.

No, OP is asking about the panels on the rear wall.

right, but I thought YOU were talking about the chair rails. my bad.

 

[Robin97396]

We had talked about the chair rail previously, but OP was calling it something else. Mostly asking if the interior skins were structural. They are technically structural, but most of us remove them and replace them with something less industrial. OP wants to strip the interior and spray foam just like so many of us do, but hers is specifically because of the heat in Mexico.

Currently struggling with the back wall panels just like most of us did. I think I spilled a little blood in the back corners of my bus trying to get the lower wall panels disconnected from the floor. Getting behind the chairlift was kind of challenging. I left both panels still connected to the floor all through the foam process just by bending them out of the way.

But, to be clear, even interior wall panels are considered to be structural by the bus manufacturers. In this environment (Oregon) I've seen quite large fir trees (4' thick) that fell on a bus and you could still crawl through the bus. By removing my interior panels I know I've taken some of that strength away even though I replaced the interior panels with plywood. I don't plan to be under any falling trees if I can help it. I also appreciate the fact that it sounds kind of softer in here now with the wood interior.

 

[Robin97396]

Almost forgot. The most current discussion on insulation was the one about wood fibre insulation. That worked it's way into discussions about neoprene panels for insulation then kind of fizzled out.

The LandRover roof is basically a solid cover that shades the actual roof of the bus. I'd like to put a photo on here but haven't learned how to do that with this device yet. If you search Landrover you should be able to find photos that show the roof configuration. It's simply a roof above the roof of the vehicle allowing air to flow through. Almost the same if you put a deck on top of your bus.

 

[Rusty-SKO]

the landrover roof is basically a solid cover that shades the actual roof of the bus. I'd like to put a photo on here but haven't learned how to do that with this device yet.

.

 

[Tango-SKO]

Makes a huge difference to drive around with your roof always in the shade. One more argument for a roof deck.

 

[Robin97396]

Another point for a roof deck. I'm told that mosquitos don't tend to bother you if you're that high off the ground.

 

[Tyania]

Anything you can add on to help shade or cover the roof to block it from direct sun will help.
For the rear wall part I can't help you with removal except just cut it out?
But I do have a few alternatives.
Instead of removing the panel's for spray foam? There is a product out there made buy (therma corp. I think) that is a pour in compound/mixture that turns into the expandable foam as it cures. At my work we use it for underground piping systems. So it is compatible with steel,copper,PVC..
We get it in minimum gallon jugs and even 55-gallon drums and we call it A and B compound where you mix (example 6- ounces of part A to 6-ounces of part in a popcorn cup and pour it into the hole in the wall opening.
Then you only have about 15 -seconds after you pour it in on a hot day before it is foaming back at you and you cover the hole and let it expand.
Good stuff and I have even insulated 1200 degree steam piping like that.
After that then you could put thin insulation and a board over that.
And or I plan on doing a 3' wides x bus width back porch with a roof that matches the bus body the same width out.
That would also provide some shade on the bus panels on the back?
Good luck.

I am digging your ideas... I don't know if I can find that filler product down here but I will search, maybe within the boat community someone can point out where to get it.
I really didn't want to go for that panel over look but the more I look at the skin (the strength that the corner curve gives it, and the upper step out of the top light box), the more I see the structural benefits. Guess I will do my best to make it look good. And it sounds like it will save me a heck of a lot of sweat and tears.
I was also going for a back porch but was thinking of something that would fold up to the back of the bus while driving to keep things short but building a more permanent deck with the roof rack hanging over would make a lot of sense. ****, plans change!

Thanks to all for the ideas and thoughts.

Almost forgot. The most current discussion on insulation was the one about wood fibre insulation. That worked it's way into discussions about neoprene panels for insulation then kind of fizzled out.

On my way to try and find that thread that Robin mentioned. The thought of neoprene as a thermal break between the ribs and new panels has crossed my mind too so that should be interesting. Since I am trying to keep the insulation space to a minimum, I am trying to use the original metal framing rather than putting in much wood (I will use a bit). So, point being I will need something over those metal ribs.

 

[Rusty-SKO]

On my way to try and find that thread that Robin mentioned. The thought of neoprene as a thermal break between the ribs and new panels has crossed my mind too so that should be interesting. Since I am trying to keep the insulation space to a minimum, I am trying to use the original metal framing rather than putting in much wood (I will use a bit). So, point being I will need something over those metal ribs.

Neoprene seems like short-term solution and it breaks-down? Maybe something more durable- tire tube or thick plastic tape? Might be able to get free used plastic banding that they use now.



Can't help singing this song after seeing the title this post.

 

[Robin97396]

There's a good number of us that don't have physical partitions in our buses, but it's quite common to tie into the ribs.

My partition in this bus is an old military parachute. It keep the center section about 5 degrees warmer. It should work the similarly for AC.

You guys are moving right along.

 

[karrlot]

Karr Family Kamping Bus: 2016

Here is a link to my blog. I had a post on 12/11/2016 about removing the interior panels on the back. I think that is what you are asking about.

For me it wasn't any different than removing the side panels or roof panels. I unscrewed any screws - like in the door hinges. I used an angle grinder and air chisel on the rivets.

I'm glad I did remove the skins because I found a leak in the window that had rusted through some of the framing. If I am looking at your photos correctly (if the top photo is turned sideways and the floor is actually on the right side of the photo) your floor looks like mine did. I found a leak that was coming in through the gasket on the window and dripping down inside the wall.

On my bus the inside panel did not hold the window in. If you look on the outside window there is a gasket around the window with a strip in it. When you take the strip out, the window comes out. I assume that if that is the case on your window also, then it would be the same.

The inside panel was tucked behind the inside of that gasket, but it just pulled out without affecting the gasket or window.

 

[Tyania]

Karr Family Kamping Bus: 2016

Here is a link to my blog. I had a post on 12/11/2016 about removing the interior panels on the back. I think that is what you are asking about.

For me it wasn't any different than removing the side panels or roof panels. I unscrewed any screws - like in the door hinges. I used an angle grinder and air chisel on the rivets.

I'm glad I did remove the skins because I found a leak in the window that had rusted through some of the framing. If I am looking at your photos correctly (if the top photo is turned sideways and the floor is actually on the right side of the photo) your floor looks like mine did. I found a leak that was coming in through the gasket on the window and dripping down inside the wall.

On my bus the inside panel did not hold the window in. If you look on the outside window there is a gasket around the window with a strip in it. When you take the strip out, the window comes out. I assume that if that is the case on your window also, then it would be the same.

The inside panel was tucked behind the inside of that gasket, but it just pulled out without affecting the gasket or window.

Yey! Thank you. It is nice to see a some pictures of the process finally.
Now the only thing that leaves me uncertain is that my back skin panel goes way behind the chair rail in my bus and even under the first set of rivets that holdthe chair rail to the bus... It looks like yours just barely tucked behind it. I guess I will plan to cut that section of the back skin out and leave it back there.
Thanks for putting that post up for me.
Funny, I could relate to your earlier post of the unfinished porch too. I built a porch roof structure for mine before starting to work on the bus and there it sits... yet uninstalled! Such is the nature of distraction and priority.

 

[karrlot]

On one side the bottom of the chair rail was rusted out, so I just cut it off. On the other side I just left that little strip of the panel there.