Ceiling panels and spray foam

[4Borns]

We are brand new to the world of skoolies and just purchased a 2007 International 36 ft bus, after several years of wonder. Nearly done with demo and have our first major head scratcher... The metal ceiling and wall panels are in excellent shape and we carefully removed, labeled and stored them in hopes of reusing them after we spray foam the ceiling and walls. Has anyone in skoolie land reused the existing panels with success?? We have read about the thermal barrier issues but can't find an outcome from folks who have reused their panels and their recommendations after the fact. We live in Colorado and the climate is dry so we're not accustom to condensation issues but would love to take our bus various climates. We would be grateful for any advice.

[Geo Jeff]

I was planning on using mine as well but I've ben told other had challenges doing it. I'm not sure why though? The condensation is not from outside sources its from breathing , showering washing dishes running propane non vented heat. The colder your climate the less moisture the air can hold and the more condensation inside you'll have. If the metal is warm it wont condensate. Hence no metal bridging from the roof to the panel where they screw or rivet on. Since the steel bus cant breath you cant put a wrap on it like a house. I think this is the idea of wood use as it is a thermal break?

Why don't cars have this issue? I don't fully understand it. Also some buses have holes in there roofing panels. Thousands of small holes on the panels I wonder if this helps it breath?

Foam looks like the trick and why you cant do metal panels over foam I'm not sure but I was sure headed that way.

[EastCoastCB]

Originally Posted by Geo Jeff

I was planning on using mine as well but I've ben told other had challenges doing it. I'm not sure why though? The condensation is not from outside sources its from breathing , showering washing dishes running propane non vented heat. The colder your climate the less moisture the air can hold and the more condensation inside you'll have. If the metal is warm it wont condensate. Hence no metal bridging from the roof to the panel where they screw or rivet on. Since the steel bus cant breath you cant put a wrap on it like a house. I think this is the idea of wood use as it is a thermal break?

Why don't cars have this issue? I don't fully understand it. Also some buses have holes in there roofing panels. Thousands of small holes on the panels I wonder if this helps it breath?

Foam looks like the trick and why you cant do metal panels over foam I'm not sure but I was sure headed that way.

Its not from breathing or cooking. My bus is empty and sweats literally gallons worth pretty regularly. I've been watching.

[superdave]

you sure can use the old metal, put a thermal break between the ribs and the metal ceiling. you could use some nice thin plywood like they use on the back of cabinets. someone on another forum asked the question show me your ceiling and i was amazed at what people put up on the ceiling. im doing t&g pine. one guy used oak slats from pallets in a fishbone pattern. someone used roofing tin galvalum color, its up to you. have fun and good luck

[DoubleO7]

the type of material used as a thermal break on the ribs under the metal ceiling panels will help keep condensation away.

Maybe.

What your trying to do is keep the moisture in the air suspended.
If a surface is cool enough, condensation may still occur.
And that "cool enough" temperature depends on the thermal break material used, humidity and barometric pressure at the time.

The term "climate control" is not just heating and cooling to a desire temperature. It also involves humidity control.

The ideal relative humidity for health and comfort is about 40-50%. In the winter months, it may have to be lower than 40% RH to avoid condensation on windows and metal surfaces.

Without humidity control, I have to wonder what these skoolies with lots of interior wood surfaces do during long term storage. Without a de-humidifier plugged in, it would be very easy for a skoolie to turn into a mold and mildew greenhouse.

[Scooternj]

Originally Posted by DoubleO7

Without humidity control, I have to wonder what these skoolies with lots of interior wood surfaces do during long term storage. Without a de-humidifier plugged in, it would be very easy for a skoolie to turn into a mold and mildew greenhouse.

That's when you seal everything with Kilz Klear

[DoubleO7]

Originally Posted by Scooternj

That's when you seal everything with Kilz Klear

Does not appear to brag about being mold and mildew resistant.

[jazty]

I did the same thing: carefully removed each ceiling panel and labelled them with a number and direction so I could put them back in after insulation. Then I thought about it more and tossed the panels in my scrap metal pile! The good scrap metal pile, that is. The one I pull from regularly.

The reasons I decided to go with a plywood ceiling and wood ribs are twofold.
One, adding a reasonable thermal break to keep the metal panels off of the ribs will change the curve of the sheet metal. None of the screw holes will line up after this. Even a thin piece of rubber will be enough to offset the screw holes.
Two, wood has much lower thermal conductivity. Even with a thermal bridge between the ribs and the steel you'll still be passing lots of thermal energy through the seventy thousand screws, which will then pass through the sheet metal. Each one of those screws will be dripping when the dew point is right.

Also, wood just looks nicer (subjective, I know)