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The 2021 Sprinter 170 was still an empty cargo van. Roof holes were already cut. There was no clay. First work on the shell was the six-layer stack, so the Nomadic could hold indoor temperature while we hike with the animals aboard.

This is the stack in the order it went in, and what each layer is for. I am not walking R-values, the EcoFlow run, or the roof AC here.

Shell first, clay last

Same garage, same 170: a gas Mercedes Sprinter 2500, high roof. The Nomadic hole, the Arctic Tern opening over the rear bed, and the MaxxAir-style fan hole already existed. Power and AC were not in yet. Brittany had not started clay. We coated metal while we could still reach it from both sides.

The six-layer stack

We count six layers, in this order. The two LizardSkin sprays are layers one and two, then Havelock wool in the cavities, then Kilmat, then 1-inch polyiso, then 3M Thinsulate, including the ribs. Each layer has a job. Mixing those jobs is how you talk yourself into skipping one.

LizardSkin on bare metal

Entire empty shell, on clean metal, before anything else. Ceramic heat-barrier spray goes on first. That product is Henkel TEROSON Thermal Control, IDH 3124339, the 1-gallon black catalog item. Then we sprayed LizardSkin Sound Control.

This is the only chance to coat the metal. Once wool, board, and walls are in, you are done touching the skin. We did not wait until furniture week and try to spray around a cabinet.

Havelock wool in the cavities

What we stuffed was Havelock sheep's wool in 16×48×2 bags, R-7, 100% wool. Framing, slider-door cavities, and anywhere a board will not fit. This was a 2021 build. Those bags are not today's Havelock R8PRO24BOX 24-inch PRO.

Wool is the fill where polyiso cannot go. Do not compress it. Leave the large flats for the board that comes later.

Kilmat is sound, not thermal

Kilmat is sound deadening. It is not a sixth thermal layer. We put it on metal in the same garage, and the photos still show it in the window cutouts. Treat it as drum control, not insulation. If you count it as R-value, you will skip something that actually holds heat.

1" polyiso from Lowe's

We cut 1-inch polyiso board from Lowe's to fill the large wall gaps between framing and the ceiling gaps between roof ribs. It is not a full-wall foam truck. The board covers the flats. The wool already took the cavities. Do not try to make one product do both jobs.

Thinsulate last, including the ribs

Last barrier before walls and the cedar plank ceiling: 3M Thinsulate sheets over everything we could sheet, including the polyiso. Then we pulled it in long strings through the roof rib channels and stuffed it into holes in the wall and roof ribs and the door cavities. This is the layer you see before walls go on. If you skip the rib strings, you leave a metal highway over your head.

What this stack is for

The stack is there to hold indoor temperature with HVAC on for Austin and Brittany, Rambi, Tilli, Torro, and Aladdin, who lives in the garage, on hike days. Insulation does not run the AC. The house bank is on the EcoFlow post.

The shell had six layers and no clay yet. Next work in this garage is the EcoFlow Independence Kit.