Admittedly only for a few small ruined corridor sections,
crashed ship scenery, but I used the insides of envelopes.
There are some nice patterns available. As I didn't need
a lot I just used letters/envelopes that came in the post,
but if you wanted to do whole corridor sections, then
simply buy a pack or two of new envelopes. Just make sure
you like the inside pattern.

I pasted mine onto thick card &/or foam board. Thin washes
of paint/ink followed by some 'gubbins' (pipework etc).
It looked passible & was very cheap.
