Campervan Insulation, Vapour Barriers & Soundproofing Guide

If you’re converting a van, you’ve probably wondered: Do I really need insulation or a vapour barrier? Can I just carpet the metal and move on? While going bare-bones might save time, it can cost you in comfort, rust damage, and road noise down the line. This is always a debate and this is my overall picture of it.

In this post, we break down the pros and cons of each layer — from sound deadening to breathable insulation to vapour barriers — and help you avoid the most common pitfalls. We also recommend top-rated products to build a smarter, quieter, and longer-lasting van conversion.

Big-picture takeaway

Think of your van walls as a three-layer puzzle:

Damping layer (optional): heavy, sticky mats that stop the metal from vibrating
Insulation layer: something fluffy or foamy to slow heat flow and absorb some noise
Interior lining: carpet, ply, or panelling that you actually see and touch

Whether you add a vapour barrier (a sheet of impermeable plastic or foil) is a separate moisture-management choice that affects every other layer.

1. Carpet straight onto bare steel

Upsides	Downsides
Fast & cheap – glue it and go	Condensation magnets – moisture builds behind the carpet and can’t escape
Zero thickness – keeps max interior width	Cold in winter, hot in summer
Lightweight	Road noise and vibrations remain
Easy to remove for repairs	Trapped moisture can cause hidden rust

When it makes sense: Short-term builds, dry climates, trades vans with minimal overnight use.

2. Add sound-deadening (CLD/butyl) first

Pros:

Reduces rattles and metal resonance (10–15 dB improvement)
Very thin (~2 mm), doesn’t absorb water
Adds thermal mass benefits

Cons:

Adds 15–25 kg weight if fully applied
Costs around £125–£250
Doesn’t block airborne noise (voices, horns)

3. Thermal insulation

Benefit	Caveat / Fix
Comfort – warmer in winter, cooler in summer	Takes up space (25–50 mm)
Lower heating/cooling costs	Use flame-retardant materials
Better sound absorption	Gaps reduce performance
Helps reduce condensation	Needs proper ventilation or risk mould/rust

Common insulation types:

3M Thinsulate SM600L – lightweight, self-adhering, great performance
Havelock Wool – renewable, breathes naturally, holds moisture safely
Foil-faced foam (e.g. Thermo-Liner) – easy to install, okay for radiant heat
Polyiso boards – high R-value per mm, but rigid and can squeak

4. Vapour barrier – Yes, No, or Partial?

Why people add one:

Prevents interior moisture reaching cold van skin
Common in home construction, so feels "correct"

Why many van builders skip it:

Issue	Detail
Impossible to fully seal	Moisture sneaks behind and condenses
Trapped water can’t escape	Van flex causes seals to fail over time
Adds cost & labour	Benefit is debatable in well-ventilated vans
Harder to service later	Wiring or upgrades become tricky

Middle-ground options:

Use breathable insulation (wool or Thinsulate) instead
Add vapour barrier only in splash zones (e.g., shower)
Use a “smart membrane” that breathes both ways

Putting it together

Layer choice	Best for	Likely pain points
Carpet only	Budget builds in warm/dry areas	Poor insulation, noise, hidden rust
Sound-deadening only	Delivery or stealth builds	No thermal comfort
Sound-deadening + insulation	Full-time use in UK	Needs airflow and more labour
Add vapour barrier too	Extreme cold or high-altitude	Hard to install and risky if not perfect

Practical Tips

Ventilation beats perfection – a roof fan + cracked window does more than a sealed wall
Use 25–30% sound-deadening coverage – focus on big flat panels and wheel arches
Use high-temp adhesives and foil tape – rated -30°C to 90°C
Inspect yearly – check behind panels with light or camera for rust or mould
Build for serviceability – never fully seal walls you’ll need to access later

Bottom line

You can skip insulation and just carpet the steel, but you’ll sacrifice comfort, sound quality, and long-term durability.

Best approach for most UK vanlifers:
Selective sound damping + breathable insulation + good ventilation — no full vapour barrier.

Recommended Products for Campervan Insulation & Soundproofing

Upgrade your build with trusted, tested gear. These are the brands we rate — based on real installs, not just reviews.

Sound Deadening (CLD Mats) Buy on Amazon UK

Dodo Mat DEADN Hex (UK favourite)
Noico 2mm Sound Deadener (budget USA option)
Silent Coat Bulk Pack

Insulation Buy on Amazon UK

3M Thinsulate SM600L (best for vans)
Havelock Wool Van Packs (natural + moisture regulating)
Thermo-Liner Pro (Foil-faced foam)

Vapour Barriers & Adhesives Buy on Amazon UK

ThermaWrap Foil VB Membrane
3M 90 High Temp Spray Adhesive
Aluminium Foil Tape (seal overlaps)

Acoustic Liner (Extra Sound Absorption) Buy on Amazon UK

Dodo Thermo Liner (6mm or 10mm)
Car Builders Mass Noise Liner

As an Amazon Associate, we earn from qualifying purchases — but every penny helps us support free van build resources, new product testing, and better solutions for UK tradespeople.

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