The metal we use.
We use U.S., made steel as much as possible.
Our floors are all 10ga. with four to five 1/4"x3" C-channel underneith.
The main hull is 12ga with 1/4" C-channel running vertically every two feet.
The roof (dome) is 12ga with 1/4" C-channel running horizontally with the top. Two to three, depending on shelter size.
The back wall is also 12ga. with crisscrossed 1/4" C-channel
Our standard door is 14ga (12ga. optional) with single throw 1/2" triple lock points with HD welded-on hinges (3)
The paint and coatings we use.
The inside paint is used on the outside of commercial jet aircraft—a highly durable brilliant high gloss oil-based acrylic.
The outside is coated with a hi-mil two-part marine epoxy. It's used for offshore saltwater drilling rigs, the underside of barges, and is approved for use on dam gates by the U.S. Corps of Engineers.