Insulation foam might not be what you think it is

I was planning to use spray foam for my 40-foot container build in Phoenix until a guy who builds them for a living told me it traps moisture against the steel. He said I'd be dealing with rust within 3 years if I didn't vent it properly. Has anyone here gone with rigid foam boards instead and seen better results?

2 comments

2 Comments

the_gray1d ago

Hang on, people have been spray foaming shipping containers for years. I've seen plenty of them in Arizona that are fine after 5+ years. The moisture thing sounds like something a guy selling rigid board would tell you. Sure, if you seal a container up tight with no vents anywhere you might get some condensation, but thats true for any build. Slap a couple of those little roof vents on it and call it a day. I think the rust risk is way overblown unless you're literally dunking it in water.

garcia.miles2d ago

Man that's a rough lesson to learn the hard way, really appreciate you sharing that heads up.