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Deciding on Airstream Insulation?

Deciding on Airstream Insulation?

Airstream Insulation is a highly debated topic among the airstream forums. Theres spray foam, reflectix, mineral wool, fiberglass, recycled denim, foam board and more. There are so many options and differing opinions.

thermasheath-foam-board-insulation-787264-64_1000We researched, debated and changed our minds. We have finally decided on two layers of polyisocyanurate  (PIC) rigid foam board. It’s water resistant and has a R value of 6 per one inch of thickness. We have a 1.5″ gap in the wall for insulation so we’re going to layer a 1″ and .5″ foam board for a combined R value of 9. Thats the highest we could get out of any of the products.


Roxul was a close second option and we still may need to use it for the endcaps. Mineral wool is great because its very heat resistant, doesn’t grow mold, and is pest resistant. If we split a batt to the thickness we need we would get about an R value of 6.

We decided against the popular spray foam insulation for a couple of reasons. To be done correctly, it should be applied by a professional and its very expensive. We don’t want our wiring to be difficult to get to. We’re wiring the whole trailer ourselves and trying to anticipate all our electrical needs and additions, but if we need to access it in the future we would prefer not to destroy our insulation to get to it.

Another factor that influenced our Airstream insulation decision, is that we’re waiting on all our wiring to arrive. We can go ahead and get the insulation done while we wait and we can easily run the wiring over the top of the foam board. We’ll be one step closer to putting the walls back up!

This is all in theory for now, the giant foam boards are waiting to be measured and cut. We will score them with a utility knife to follow the curves and then seal the seams with foil tape. The last step will be applying double sided tape and foam sill seal (polystyrene roll) to cover all the ribs. I’ve read a couple folks have done this and it seems like a great way to help prevent the ribs from conducting cold and heat from the outer skins to the inner skins.

We’ll update with photos and let you all know if we run into any issues as we begin the insulation process, so make sure to follow our blog to receive updates!


Here are some of the blogs, groups and resources that helped us when researching Airstream insulation –

Air Forums

Airstream Addicts

Airstream Argosy Owners


The Greatleys



Wednesday 21st of July 2021

rigid foam on a curved body - you mentioned cutting it along the curves, but i'm curious how this will work. we just got an argosy and i'm looking at insulation, so i'll have to look around and see if you posted more about how you did this.


Monday 22nd of June 2020

I can't find the update to this. Was it ok to get the rigid foam in the rounded walls? Do you have pictures? Thanks!

Valerie Jackson

Sunday 14th of April 2019

Where did you find the 1 inch R-max? Can only get the 0.5" at lowes/Home depot.

Deciding on Airstream Insulation? - Vintage Airstream Argosy Renovation - RV Blogger

Tuesday 6th of November 2018

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Gary Snyder

Wednesday 12th of September 2018

Great review. I'm almost at that stage myself with my '74 Argosy, but am still thinking about spray foam as it would add to the rigidity of the trailer and prevent possible dents that are bound to occur. I'll update you on the cost when I get an estimate. I'm estimating I'll need about 500sq ft. Keep you posted.

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