Trailer Questions

[tigerstyle]

Looking for a bit of technical advice on trailers, boringly specifically wall construction!

What is the type of wall material used in a trailer like this? 
Helping a friend of a friend with some ideas if windows can be cut into them, or how much weight they can take from unistrut hung inside etc? 

Material, thickness? 


Then something like this, a little bit more flash, are the walls any different?

[Magenta Sunset]

bottom pic looks remarkably like a caravan chassis/custom body.
caravans are double skinned. Ally (& or) Grp/composite outside, wooden battens, and ply/hardboard inside with (for a van) insulation in between.

[tigerstyle]

Ok cool, both of the pics are standard Ifor Williams trailers.

[Magenta Sunset]

only thing to remember is 1, buy windows before cutting anything. and 2, id double skin, to insert timber round all 4 sides to brace the panels.

[Dum-Dum]

Probably fiberglass or a fiberglass foam sandwich.