GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Plus Icon Minus Icon Picture icon Hamburger Icon Close Icon Sorted

Community and Q&A

Insulating an aluminum cargo trailer

smithksor | Posted in Green Building Techniques on

Hello greatest community on earth!

I am going to insulate an enclosed cargo trailer and I am pretty sold on the expanded cork for the project. My question is what other products should be applied in addition to the cork insulation…do I need a heat shield of some sort between the aluminum siding and the cork and then on the inside, do I need a vapor barrier between the cork and the inside pine paneling?

Any advice is greatly appreciated.


GBA Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.


  1. GBA Editor
    Martin Holladay | | #1

    It would be helpful to know your climate zone (assuming that this trailer will be parked rather than roaming north to south and south to north).

    I'm not sure that you have thought this through. If you have thought this through, tell us more about your plan.

    1. What type of adhesive, if any, will you use to attach the cork to the aluminum?

    2. Is the aluminum curved?

    3. How thick is the cork?

    4. What is your plan to handle the expansion and contraction of the aluminum?

    5. Will this trailer have electrical wiring? If so, where will you run the cables?

    6. Will you be installing studs or other wood framing?

    7. What type of interior finish materials are you considering?

  2. smithksor | | #2

    Thanks Martin.

    I'm just in the beginning planning stages. The trailer will be primarily in the climate zone 3 - western Oregon. The plan is that it will primarily serve as a storage unit for some stuff, but be ready for me and my son to hook it up to the truck and basically use it as a hard shell tent for weekend camping trips. Right now there is no desire to make it fancy, just want it to hold heat and keep the rain out. Just throw our camping cots in there and stay dry.

    1. I don't know about adhesive, I wasn't sure if there needed to be something in between the aluminum and the cork - it gets pretty warm in the summer to touch. I was contemplating dynamat superlite on the aluminum, then the cork, but I'm open to any suggestions.

    2. The aluminum is curved in the corners.

    3. I was thinking of 2" of cork.

    4. I don't have a plan, open to suggestions.

    5. Minimal electric wiring, just planned on our led camp lanterns for light. There is some existing electrical that goes to a light. If i was going to run lights, I'd put in some flex conduit to run the electric.

    6. It has 1/8 in plywood now, I was thinking of replacing that with 1/8" FRP (fiber reinforced plastic).

    7. I was going to coat the sidewalls and roof paneling with durapoxy from kelly-moore (unless I buy the FRP).

    Again, the goal is to keep the primary purpose of the cargo trailer to be a cargo trailer, but be used during the summer months as a type of hard shell tent for camping, not doing a full camper conversion to the cargo trailer. I'm concerned about moisture and mold growth though, I don't want to do anything that will cause that to happen.

  3. GBA Editor
    Martin Holladay | | #3

    Walter gave you good advice. The obvious barriers to success for you are that (a) I doubt whether 2 inches of cork can conform to the curves (you can determine whether my hunch is correct with some experimentation), and (b) you need to come up with a structure to which you can attach your interior finish material (the FRP).

    My guess is that you are going to end up with some type of thin (flexible) "rigid" foam, followed by framing materials (maybe 1 1/2" by 1 1/2"), with spray foam between the framing, followed by your interior finish panels.

    You might want to look for a web forum for Airstream trailers.

  4. smithksor | | #4

    OK, I saw another post about polyester insulation, but it looks like no one manufactures it any longer. Are you aware of any?

  5. GBA Editor
    Martin Holladay | | #5

    There used to be three brands of polyester insulation available in the U.S.: Dow SafeTouch, EnGuard insulation, and Rtica insulation. All three insulation products have been withdrawn from the market due to poor sales.

  6. walta100 | | #6

    Aluminum is a very good conductor of heat filling the voids in a aluminum structure with insulation is a waste of time and money.

    The most important detail in this project will be eliminating every thermal bypass. This is to say no aluminum part on the inside of the structure is connected to any aluminum part on outside of the structure without a thermal break. So you need to build a new self supporting trailer inside the trailer and fill the gap between them with insulation.


Log in or create an account to post an answer.


Recent Questions and Replies

  • |
  • |
  • |
  • |