Campervan Insulation Guide
The complete guide to insulating your campervan for UK conditions. Compare 7 popular insulation materials with R-values, costs, and installation advice.
Good insulation is the single most important factor in making your van comfortable year-round. Get it right and you'll stay warm in Scottish winters and cool in summer heatwaves.
Quick Comparison
Compare all 7 insulation types at a glance. Click any row for full details.
| Material | Cost/m² | Difficulty | Moisture | Condensation | Eco Rating | Best For | |
|---|---|---|---|---|---|---|---|
Celotex / Kingspan (PIR) | 6.5 | £8–15 | excellent | low risk | WallsCeilingFloor | ||
Sheep's Wool | 3.5 | £12–25 | excellent | low risk | WallsCeilingWheel arches | ||
Dodo Insulation | 4.0 | £15–30 | good | low risk | WallsCeilingFloor | ||
Spray Foam | 6.0 | £20–45 | excellent | low risk | WallsCeilingFloor | ||
Thermawrap / Bubble Foil | 1.5 | £3–8 | good | medium risk | Behind claddingOuter skin layerDoors | ||
Rock Wool / Mineral Wool | 3.3 | £5–12 | fair | high risk | FloorBehind cooker | ||
XPS Foam Board | 5.0 | £6–12 | excellent | low risk | Floor |
Detailed Breakdown
Everything you need to know about each insulation type for your campervan build.
Type: Rigid Foam Board | Also known as: Celotex, Kingspan, PIR Board, Polyisocyanurate
PIR (Polyisocyanurate) rigid foam boards are the most popular insulation choice for UK campervan builds. Sold under brand names Celotex and Kingspan, these foil-faced boards offer the best thermal performance per thickness of any widely available insulation. The foil facing doubles as a vapour barrier, reducing condensation risk.
Pros
- Highest R-value per inch of any common insulation
- Foil facing acts as vapour barrier
- Rigid and easy to cut to shape
- Lightweight — won't add much to payload
- Doesn't absorb water
- Available at all UK builders' merchants
Cons
- Difficult to fit around curves and irregular shapes
- Gaps between panels need sealing with foam tape
- Not eco-friendly (petrochemical-based)
- Can be brittle — snaps rather than bends
- Produces toxic fumes if burned
Not Recommended For
Wheel arches, Curved surfaces
💡 Installation Tips
Cut slightly oversized and friction-fit between ribs. Seal all edges and joints with foil tape to maintain the vapour barrier. Use 25mm for walls and 50mm for the floor if space allows. Combine with Thermawrap on the outer skin for maximum performance.
Area-by-Area Recommendations
Different areas of your van have different insulation requirements. Here's what works best where.
Best Materials
Needs compressive strength to support furniture and foot traffic. XPS is ideal. Lay insulation, then 9-12mm plywood on top. Use Thermawrap as a first layer for extra moisture protection.
Best Materials
PIR boards friction-fit between ribs give the best thermal performance. Fill gaps with sheep's wool. Apply Thermawrap on the outer skin first for a reflective layer.
Best Materials
Lightweight is key — avoid heavy materials. PIR boards between ribs with wool stuffed into gaps. Dodo's self-adhesive products work well overhead. Ensure a vapour barrier to prevent condensation dripping.
Best Materials
Irregular curved shapes make rigid boards impractical. Sheep's wool stuffed into the cavities or spray foam for complete coverage. These are major cold bridges — don't skip them.
Best Materials
Limited depth available. Dodo's thin self-adhesive products or Thermawrap work well. Stuff wool into any cavities. Doors are often overlooked but are significant cold spots.
Best Materials
Fire safety is paramount. Rock wool is A1 non-combustible — the only safe choice directly behind a cooker or heater. Use at least 25mm thickness with a reflective heat shield.
Recommended Insulation Combos
Most successful van builds use a combination of materials. Here are three proven approaches.
Good for weekend/summer use. Adequate for 3-season UK camping. May feel cold in deep winter without heating.
The most popular combo for full-time UK vanlife. Excellent 4-season performance with a diesel heater.
Maximum thermal performance with zero thermal bridges. Ideal for full-time living in all UK conditions including Scottish Highlands winter.
Ready to Plan Your Build?
Now you know how to insulate your van, use our tools to plan the rest of your conversion.