For a while, my friend that runs an auto shop had a military container that had slide out sides like an RV.

It was pretty cool. A 40' IIRC and almost the entire length of both sides slid out, making it about 22 feet wide when fully extended.

Except he said it leaked really bad. Pert near gave it away because of the leaks.

 

on the container? nothing, and it stays bone dry

even in the worst humid/wet conditions, the container is always dry ...... the floor is wood and will probably be an issue some day. it sits on 6x6s, but pretty much has settled onto the dirt; I think