The NV’s walls seem to be designed differently than most vans—it has a second, interior wall that make the sidewalls straighter than other vans. This is a feature designed to make it easier for tradesmen to attach shelves and cabinets. Because of this, I went round and round on how to insulate the walls. Finally, the idea of bubble wrap plus R-Max foam board felt right, so that’s what I went with.
The R-Max has a foil side designed to act as a heat shield. In order for it to work, you need to provide an air space between the heat and the foil. Feeling that the space between the inner and outer walls was too much, I filled it in with the bubble wrap (a little concerned it would melt if it got too hot, but a contractor/camper/neighbor assured me it wouldn’t). I then covered the bubble wrap with 3/4″ R-Max.
For the roof, I taped up a single layer of bubble wrap between the studs (to ensure the air gap) and pushed in a single layer of R-Max 3/4″. I had intended to put up two sheets of R-Max, but the one lined up nicely with the roof studs, so I took that as a sign to leave it as is. Time will tell.
I made a mistake and forgot to put bubble wrap under one of the roof panels, so it will be interesting to see if the lack of bubble wrap has any affect on the that section.
For the roof, the R-Max is held in place by simple friction/pressure. I plan on covering it next with paneling which will more securely hold up the foam board.
For the sides, I used the Teks screws (screwed into the interior wall’s studs), but I really should have used flat-head sheet metal screws with washers as the Teks would often over-penetrate the soft foam. The intention was to also cover the sides with paneling—so I wasn’t concerned about the panels coming loose—but now I’m thinking of covering the sides with fabric (possibly sheets or curtain fabric), so I may go back and re-attach the sides with the metal screw/washer combination.
The total insulation probably took about 4 hours so that wasn’t too bad. The hardest part
was waiting for a plan to clarify, sorry, was deciding.