I re-insulated my westy this summer. Stripped the interior completely. Stock
insulation (yellow fibreglass) was found in all the wall cavities. As noted
by Frank Condelli and Matthew Bulley, the wall behind the fridge is the most
susceptable to rust problems. On my van the rust was not too bad and limited
to the lower seam, where the wall meets the floor.

Only other area that had rust was the bottom of the cavity immediately
beside the rear bench seat (right hand side), just a little bit of surface
rust, again where the wall meets the floor.

I gound out all the rust, treated the areas with a "rust converter", then
painted with Tremclad. Aftert the paint had dried I sprayed all the interior
body seams with "Rust Check".

Condensation is often cited as the cause of this rusting, I agree but want
to add that the westy service boxes and fridge exhaust are also places where
water can get ino the walls. Seal those areas with your favourite caulk.
(now thats a sentence to be written and not spoken).

During this re-insulation job, I soundproofed my van with a kind of roofing
membrane called "ProGard" made by EMCO. Its a rubberized asphalt material
with a polyethylene mebrane on one side and self adhesive on the other I was
to cheap to go the "Q-pad route, this stuff cost around Can$70 for a 3'X 65'
roll. While it is only around 1/8" thick, you can stick on as many layers as
you want. This stuff does have an odour, noticable during the install on a
relatively hot day. But once in place I can't smell it at all.

After the membrane, I re-insulated with pink fibreglass and installed a
polyethylene vapour barrier. I worry that the vapour barrier could be a
problem, trapping any moisture that does get into the walls (from the
service boxes for example). Glad I sprayed a liberal amount of rust check
along the bottom of the walls.

Alistair