Redlightning- Thanks for the kind remark on my write up. For those that don't read that write up, I'm converting a cargo van into a camper. I live in Alaska, my goal is to keep heat in for about 9 months of the year.
The side panel were easy to remove in my cargo van. Of course there were no panels/head liner to deal with in the rear ceiling for me.
The side panels are surprisingly voluminous; deep from the inside to the outer sheet metal of the van. Think 4 to 5 inches deep in some places. They have support structures in them which adds to the challenge of insulating the space. There are plastic bags filled with soft foam along the lower edge of all of the panels. I continued to use 1 inch thick R-Max insulation, a polyisocyanurate foam, which is what I used above the head liner in the front. It has a higher temperature rating than polystyrene foam. With the wisdom of 20/20 hind sight, I'm not sure I'd use rigid foam again in the lower sides of the van. Its VERY time consuming to custom fit foam into a three dimensional jig saw puzzle. I kept telling myself, "I just need to do this once...." I used some blow foam to fill smaller gaps and to hold the foam firmly into place to help prevent squeaky sounds when driving. And squeaky noises are one of the "hazards" of using rigid foam. You can see in the attached pics that I'm blowing foam around almost all of the edges in the ceiling panels as well as putting a lot in behind the foam to firmly hold it in place.
Just how time consuming is it? Well, I'm a bit embarrassed to admit that I spent the better part of a day (6 to 8 hours) doing each of the 4 large cavities in the rear of the van. (Two above and behind the wheels, the sliding door and opposite the sliding door.) If you have a kid that needs a project.....
Alternatives to rigid foam are regular fiberglass insulation and the increasingly popular polypropylene insulation- the stuff that's used in jackets. The Sprinter forum and other conversion sites have tons of discussion on the pros and cons various insulating alternatives. Both of those would be much quicker to use but they also have draw back- like retaining moisture and keeping the stuff in place in a bouncing vehicle. There's no right answer on insulation- you simply have to decide what fits into your plans.
Some people also use copious amounts of blow foam. Fast and easy- but you run the risk of pushing out the sheet metal- an unsightly bulge. And the sheet metal is surprisingly thin on these van. (I know from cutting a hole in the roof to install a ventilation fan.)
The ceiling of the rear of the van was pretty straight forward to do with foam board. However, in a passenger van you may have the problem that the 1 inch foam is too thick. I spent some time trimming edges and trying to get a good fit against the roof. But the 1 inch foam still intrudes into the passenger space relative to the structural beams in the roof. Plus the structural beams are some what thicker in the center of the van compared to the edges. I'd guess that 1/2" foam would work pretty good with a just bit of work to get a good fit.
I think I've used four 4 x 8' sheets of 1 inch foam and about half of one sheet of 1/2 inch foam so far. This project is getting dragged out much longer than expected.
Pictures-
1. (6800) The rear ceiling of the van with no insulation in the last part, between the C and D pillars/roof beams. (The C pillar is behind the sliding door.) I used noise deadening material on the ceiling before installing the insulation.
2. (6799)- The panel behind the drivers seat filled with foam.
3. (6798) The rear passenger side panel filled with rigid foam. You get an idea on the jig saw work that goes into filling the space.
4. (6797) The roof beam above the C pillar on the passenger side of the van. You can see how the foam is "proud" to (above) the beam.
5. (6796) Compare the edge of the foam to the shape of the roof beam- you can see how the roof beam is thicker going toward the center of the roof, which is to the right in this picture.
6 and 7. (6794 and 6795) Similar to 4. The roof beam above the C pillar on the passenger side of the van. You can see how the foam is "proud" to (above) the beam.
8 and 9. (6793 6792) and I just fastened 1" foam to the ceiling using blow foam. The foam is held in place with fiberglass wands used to mark a driveway edge. Or in my case, they support the wires in my portable electric bear fence....
Good luck with your project- hope this helped.
