Rust on underbelly

[WildMontana]

This is some rust on the underbelly of a 1974 airstream we are considering buying- can anyone recommend whether this is fixable, or potentially a dealbreaker? I’m not sure if the rust is because of interior or exterior influences, but it looks like it goes all the way through- it’s not under the water heater or bathroom, I don’t think. Would this be providing direct access to the wooden subfloor and potentially causing rot, or could there be something else between those layers? Is it possible to patch this, or would the full panel need to be replaced? Thanks for any advice you can provide to these newbies!

[DryFly]

The corrosion you're seeing on the aluminum skin of the underbelly isn't unusual for a trailer of that age, but this certainly looks ugly. Hard to tell from a photo, but the rust on the cross member seems to be surface rust. However, you really need to do some serious poking around both above and below. Check everywhere inside - especially beneath windows, in the front, in the bathroom, and especially at the rear. Do a search for rear end rot or rear end separation and then test it for that. Get yourself an endoscopic camera and take a look inside the floor cavity, and look at the outriggers. Your goal is to determine how much of a rebuild you'll have to do. I'll bet you'll see a lot of work waiting to be done.

Buying and owning a classic airstream has a certain cache, but it can also come with a lot of pain at great expense. Proceed with caution.

[J. Morgan]

The corrosion itself is by no means a deal breaker, that can be repaired or patched over pretty easy.

That said, it may be indicative of other problems.

A trailer of that vintage is almost always going to have floor rot under the bath area, and some rot under the windows.

None of that has to be expensive to fix if a persons handy, but a repair means taking all of the bath fixtures and inner skins out replacing the floor and putting them back.

I have two trailers of similar vintage, one required a bath floor replacement and the other didn’t. My GUESS based upon your photo is that that trailer will need that fix.