Sprinter Insulation and Window Coverings
Van insulation seems to be a hot topic of debate among converters. Lots of opinions, most of which are not grounded in any scientific data other than to avoid fiberglass (yucky for lungs and skin if you get exposed to its dust). I did find some really helpful postings, with Sprinter Van USA being one of the best; they list and compare a heap of options.
After a bit of research, I visited a couple of local conversion shops to see what the pros do. Both local shops I visited use a bit of sound dampener on large metal panels, a thin layer with reflective properties, topped off by automotive grade Thinsulate. I opted to do the same and used:
Noico 80mil butyl sound dampener, 36 sqft
This stuff is primarily used by the folks that install kick butt stereo systems in their cars and trucks. When applied to a large metal surface, it prevents it from acting like a drum and instead dampens audio waves as they transfer their energy to the metal surface. If 30-50% of a large, uniform surface is covered, this stuff will do a great job dampening any vibrations and cut down on any sounds making their way into or out of the van. I put it on all the larger, regularly shaped surfaces that Mercedes didn’t already apply their own dampener to. It goes on easy: just cut it and peel the backing off to expose the sticky side. I did cover the entire surface of the wheel wells as they transfer a lot of road noise. This made a huge difference, making for a quieter ride even before adding any other insulation. This stuff doesn’t have any thermal insulating value and it is stiff to work with when it’s cold. I had to buy a heat gun in order to warm it up enough to make it pliable in the 32F temps I was working in. Since you don’t have to cover every inch of surface, cutting and applying this goes pretty quick.
Both shops use a layer that has reflective properties. The one I liked best is Thermozite. It’s made from recycled plastic bottles, it’s a bit less than a half inch thick, and it has a thin aluminum layer on one side. With an R1.3 value, it’s not very insulating but it can handle moisture and has great sound dampening properties. I covered all the walls, ceilings and doors with it. I glued it on, soft side against the metal, reflective side facing into the van.
Pricey but great stuff to work with and perfect qualities for this application. It adds another R5.2 and great sound absorbtion. One of the shops glues it backing side out, the other backing side in. I did a bit of both. On the walls I wanted to try to enhance the reflectivity of the Thermozite by giving it some breathing room. In theory you really want a layer of air on one side of the aluminum; I figured the loft of the Thinsulate is somewhat airy. Who knows. On the ceiling, I glued the backing to the aluminum with a good dose of glue, hoping it will hold up over time.
I opted not to add a vapor barrier. I figure it would be close to impossible to get anything decent in place. Plus, even with a vapor barrier, there will no doubt be condensation in those walls, what with all that metal, weep holes along the base of all the panels, and leaky trim pieces. There’s just no way there won’t be moisture in there at times.
Glue: 3M 90 spray glue is awesome stuff! Overspray is super easy to avoid with the built in nozzle control. And its qualities are perfect for the temperature swings in a vehicle. I used a total of 5 cans.
Removing the headliner: What a bear...If this beast hadn’t come with a stock headliner, I probably wouldn’t complain. But since it’s there, I’m going to make use of it until I have the time to add upper cabinets. It does give the inside a nicely finished look. Removing it can be a bit confounding. There are two approaches: take the front cab headliner down and work your way back or start from the back and avoid taking the cab headliner down. One of the shops I visited does the former, the other the latter. Choose your poison. Both approaches are a bear. I didn’t want to take the cab headliner down so I carefully started from the back. With auto trim tools, remove the rear poprivet fasteners and at each panel junction, carefully pull the seam down to access and remove the central black poprivets. As for the gray fasteners: they are the bear. If you’re tenacious, you can pry them out of their metal holes; you have to try hard to slip a very thin blade between them and the metal and then slip your forked trim tool in to compress the rivet shaft and pop it down. If you get it right, this works pretty well. You’ll still inevitably break a few. If you don’t have the patience, just yank down on the headliner, break the little suckers, and replace them when you’re ready to reinstall. Some folks don’t even bother to use plastic fasterners again and instead drill a few holes and just use truss screws to hold the headliner in place. I ended up doing that but using Mac Trak anchors, one on each side of each panel seam. They hold the headliner up while providing mounting points for D-rings to hang hammocks and other things from the ceiling.
Insulating the cab area: our van came with a ‘winter package’ that includes some lame insulation in the front, mainly on the floor. Peeking above the cab area with the headliner removed, it was evident that none was put in up there. We were able to slide a 36”x60” piece of Thinsulate between the cab headliner and the roof that should provide adequate coverage up there.
Insulating the floor: I used 1/4” thick closed cell foam strips in the floor wells and a sheet of 1/8” foam on top of that. The stock flooring fit over it. This really helped reduce road noise a lot.
Windows: lots of heat is lost and gained via the big front and side windows. I bought a large CoverKing cover for the front windshield for $30 on Amazon. And a couple of rolls of 48” wide Reflectix, some gaffer tape to attach some tiny but strong magnets. An hour of careful cutting is all it took to craft covers for the door and back windows.
Insulating was tedious! My goodness. Between taking all the door panels and headliner off, measuring and cutting and gluing countless pieces - and doing so for 3 layers! - I will always appreciate this hidden effort on hot summer days and cold winter nights. Cuz once the walls are up, all that underlying work is hidden away.
