Thermal break failure in my container roof - moisture everywhere

Last winter I built out a 40ft high-cube container in Ohio and thought I'd sealed the roof joints well enough. By March I had water dripping down the interior walls because the thermal bridging created condensation pockets I never planned for. I ended up tearing out the ceiling panels and adding closed-cell spray foam with a proper vapor barrier. Has anyone else dealt with moisture issues from container roof seams?

2 comments

2 Comments

the_lee8d ago

Yeah that "thermal bridging" thing got my buddy Mike on his build too, he had to gut his whole ceiling after one Ohio winter just like you did. Did you put any venting gaps in the foam or just seal it solid?

keith_henderson8d ago

Well, "seal it solid" is exactly what I'd tell someone to do actually. Air sealing is way more important than giving moisture a place to escape if you ask me. All that venting stuff is just an old school way of dealing with leaky construction that shouldn't be an issue if you do the job right the first time. A properly sealed ceiling with closed cell foam on the roof deck is basically a vapor barrier and an air barrier all in one. Your buddy Mike probably had the same problem a lot of guys do where they don't dry in the house fast enough before the foam goes up, and then the moisture gets trapped from the ground or the weather.