2010 Express AWD build,The Gnarvan

[86Scotty]

Nice progress and great info! Thanks for sharing some upgrade options on the newer Chevys. There aren't nearly as many here on the board but there should be. The build is looking great.

Without knowing how you want to lay out your interior it's hard to offer any advice placement. Can you post a pic, drawing or whatever or describe your desired layout?

[TeleSteve]

Originally Posted by 86Scotty

Nice progress and great info! Thanks for sharing some upgrade options on the newer Chevys. There aren't nearly as many here on the board but there should be. The build is looking great.

Without knowing how you want to lay out your interior it's hard to offer any advice placement. Can you post a pic, drawing or whatever or describe your desired layout?

I am doing pretty much a standard RB-50 floor plan. I am trying to keep the area below and behind the rear seat as open as possible for storing skis.

[TeleSteve]

I finally made a decision as to the location for the MaxxFan. I wanted it near the rear of the van since I don't have any windows except the front. I chose to offset it to the driver side so there would be more room on the passenger side roof for a cargo box or just general rack storage. If the vent was centered it either had to go all the way too the front (less air movement in the back) or the roof box would need to be far forward on the roof (harder to get to and limits available space if I get solar panels.) Right now I only have a Yakima cross bars a and Thule roof box, but I plan to build a full roof rack down the road with a passenger side mounted ladder.
So I carefully marked out the vent location so the edges would hit a high rib of the roof and clear the cross members and drilled four holes at each corner, then I taped around the cutout to prevent scratching the roof. I then painted the cut edges to limit corrosion and ran butyl tap around the opening doubling it up in the low ribs of the roof. To stiffen the opening and provide a solid backing for the vent screws and the headliner on the bottom I welded a metal frame using 1"x1" tube. The was removed and painted then attached with screws to the roof support and the back roof lip. Then I placed the roof flange in place and drilled all the holes for the mounting screws, and marked the edges for roof sealant. Then then black sealant was applied to the roof and the mounting flange was screwed down and then the vent assembly was attached.

[TeleSteve]

I put my Yakima cross bars on and the vent sits about 1/8" higher than the bars. It also only gives me about 1/4" of clearance to the garage door opening if backed in and about 1" when pulled in forward. The approach to the shop is pretty steep:

[TeleSteve]

With the fan in I could move onto finishing the insulation. I already had CLC tiles attached to the walls for sound deadening so the first layer of insulation on the floor and walls is Frost King Foil and foam duct insulation from Home Depot. This is a foil backed closed cell foam with a self stick adhesive, it is 1/8" thick with a R value of 3. This stuff also works really well as sound deadner (maybe better than the CLC tiles, had I known I would have skipped those.) I also used this on the wheel wells and gas filler bubble it conformed nicely to the round shapes.

[TeleSteve]

The next layer of insulation was Ridged foam, 1" on the walls and 5/8" on the ceiling. I used foil duct tape around all the panel edges to limit squeaking and seal the foam to limit loose foam balls. The foam was cut tight to fit between the wall and roof supports so it just squeezes in place for a nice snug fit.

[TeleSteve]

The front headliner was too close to the roof and the ridged foam would interfere with the side curtain airbags. So the front section got foil and foam followed by 1" foil backed denim duct insulation, then reflectix. A little 3M spray adhesive was used to help hold the denim insulation and reflectix in place:

[TeleSteve]

I plan to add a layer of Reflectix insulation to the back of the wall and ceiling panels when they go in, this should provide a air gap between the ridged foam and reflectix for a better radiant barrier.
With the ceiling insulation done except for the reflectix layer I started on the headliner. I am using 3/16" Sintra (Foam core PVC board) for the backer and will use standard automotive foam backed headliner to match (as closely as possible) to the factory headliner over the front seats. (Update, I would not use the Sintra for a headliner again, it deforms with the heat of a roof and no longer sits flat. I will be redoing this with Luan plywood at some point)I wanted the headliner to be have hidden fasteners so I am using Au-Ve-Co #12134 Trim panel clips. These require a ~3/8" hole in the Sintra and 5/16" hole in the roof braces to snap into. Because of the clip design the wholes need to be offset by ~1/2". To do this I placed the Sintra board on the ceiling shifted back about 1/2", temporally braced it and located and drilled 5/16" holes through the Sintra and into the roof supports. To secure the board I stuck the clips just through the holes to hold each location in place. I then took the Sintra panel down and enlarged those holes to 3/8" and installed the fasteners to the panel. I then reinstalled the panel to test the fit. These fastners sit flush on the finish side and won't telegraph through the headliner fabric, they are also easy to snap in and out, and much more durable than the plastic X-mas tree fasteners.

Here is how they attach the Sintra:

[TeleSteve]

Here is the middle section of the panel test fitted in place, I used 5 panel fasteners at each roof support. I couldn't find Sintra larger than 4'x8' so it will be two panels split at the rear most roof support. the sides are a bit wavy now, but they will be supported by the wall/ceiling trim panels.

I still have to make the rear most panel. I haven't picked up the headliner fabric yet, but when I do the Sintra panel will be sanded and both the headliner fabric and Sintra will be sprayed with high temp contact adhesive and stuck together. I will glue a layer of reflectix on the top side before installing the completed headliner.

[86Scotty]

Man, I didn't even know Au-ve-co was still around. I bought some of their epoxy a few years ago and it was the best around. It was about $25 for a small amount but worked amazingly well.

Lookin' good!