Wall covering in food truck

[Rib bonez]

For anyone who has built or assisted building a food truck / trailer what did you use behind the stainless steel for a wall panel? I’m applying fire retardant foam insulation and was going to use OSB then stainless steel. I’m getting a bit nervous about using the OSB directly under the stainless. What are other options about 7/16 or 1/2” thick?

 

[Stingerhook]

I would think BC plywood would give you a smoother surface to bond to.