Van Insulation for Beginners: The Full 7-Step Method

Step-by-step walkthrough. Step 1 — Strip and clean (4-6h): pull interior panels, cargo liner, floor mat, factory insulation. Vacuum every crevice — I've pulled 2kg of dust out of used Sprinters. Wipe the steel with IPA or a strong degreaser (Armaflex glue won't bond otherwise). Spot any rust, treat it with Fertan, let it cure 24h. Step 2 — Sound deadener (2-4h, optional): butyl rubber sheets like Dynamat or Kilmat on large flat panels. 30-40% coverage is enough — full coverage is overkill. Highway noise drops noticeably, budget €50-80. Step 3 — Seal seams + pull wires (1-2h): Sikaflex 221 in all body seams. Run your electrical now (solar, rear lights, speakers) — after insulation you can't. Label every wire with tape. Step 4 — Structural cavity insulation (3-5h): Thinsulate SM600L nominal 38mm (42mm measured loft per 3M SAE J1355) friction-fit into doors, roof ribs, pillars. Zero spray foam. Keep door drainage holes at the bottom unobstructed. Step 5 — Walls and roof (8-12h, the big job): Armaflex 19mm with 520 contact glue. Cut pieces 1-2cm oversized, glue both surfaces, wait 10-15 min tack time, press firmly. Overlap seams 1-2cm and seal with Armaflex tape — that's your vapour barrier. Work top-to-bottom so gravity helps. For curved roof corners, score the back every 5cm to let it flex. Step 6 — Floor (3-5h, full-timers only): XPS extruded polystyrene 20-30mm cut between the cross-members, 9mm plywood on top, vinyl or wood as finish floor. You lose 30-40mm headroom but gain serious cold protection. Step 7 — Windows (2-3h per window): Reflectix backed with 9mm Armaflex, shaped to each window. Neodymium disc magnets glued to the frame hold the insert in place. Five minutes to pop in at night. Windows typically account for 15-30% of heat loss in a standard van conversion (up to 30-50% in poorly insulated builds with large window areas) — don't skip this.