306oc - Peugeot 306 Owners Club & Forum

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?

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.

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

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.

Probably fiberglass or a fiberglass foam sandwich.