Armaflex AF 19mm in a van: what this NBR foam actually delivers

Let me tell you what works and what doesn't. The win: closed-cell structure means no mold growth inside the insulation — ever. That's the single biggest advantage over 3M Thinsulate, sheep wool or recycled denim for a vehicle that sees condensation cycles every single night in winter. The vapour barrier is baked into the foam itself, so you don't need a separate polyethylene film on the warm side. One less step to mess up.

The drawbacks. First, the chemical smell. For 1-2 weeks after install your van smells like a tire factory. Ventilate aggressively. Second, the price: a Sprinter L2H2 eats €400-500 of Armaflex plus another €60-80 of glue. Third, the compression trap — if you squeeze the foam behind a frame member, you lose your R-value. Press gently, don't cram.

The seams are where this system lives or dies. A vapour barrier with leaky joints is not a vapour barrier. My method: butt the edges with 520 glue, scuff the mating faces lightly, then cover every seam with aluminium Armaflex tape. On a Sprinter L2H2 solo, that's a 12-18 hour job. With two people (one cutting, one gluing) you can drop to 8-10 hours.

Double layer (38 mm total)? Only if you winter in Scandinavia or at 1500 m+ year-round. In temperate Europe or most of the US, 19 mm done properly beats 38 mm done sloppy. And please — if you add a reflective layer on top, give it a real 15-20 mm air gap on battens. Slap it directly onto the Armaflex and you trap condensation in the sandwich.