How to insulate a van: a step-by-step guide

Thinking about converting your van or simply making your campervan warmer for winter? Van conversions are a fun project, and a well‑insulated van stays cosy in cold weather, cooler in summer and quieter on the road. With so many options and van insulation advice online, it can be hard to know where to start.

That's why we've created this step-by-step guide on how to insulate a van, from the materials and tools you'll need to installation steps. Ready to start? Let’s dive in.

What's covered:

• What materials do I need for insulating a van?
• What tools do I need for insulating a van?
• How to insulate a van step-by-step
• Preparation
• Insulating the floor
• Insulating the ceiling and walls
• Insulating the windows
• Extra van insulation tips
• FAQs

What materials do I need for insulating a van?

Before you start cutting boards or sticking foil, gather everything you’ll need. Let’s break it down into clear categories so you can tick them off as you go.

Insulation materials:

• Sound deadening mats: These are usually the first layer applied to bare metal. They stop vibrations and eliminate that “tinny” echo you hear in an empty van. Once fitted, they make driving noticeably quieter

• Rigid foam boards (PIR or XPS foam insulation): Best for large, flat areas such as floors, ceilings and the van's side panels. They deliver excellent thermal performance without adding too much weight. PIR or XPS foam boards work well, and Celotex is a popular brand that many DIY converters trust.

• Insulation roll: Wool insulation like glass wool or sheep's wool works well for awkward cavities where rigid boards won’t fit. If you prefer a modern alternative, 3M Thinsulate offers great flexibility and moisture resistance.

• Reflective foil: This layer helps reflect heat back into the van in winter or away from it in summer. It often doubles as a vapour barrier to prevent condensation from causing rust. Foil-faced bubble wrap or multifoil products are common choices.

Installation supplies:

• Plywood battens to create a secure framework to hold foam boards firmly in place

• Plywood sheets for the subfloor

• Aluminium foil tape: Use this to seal joints and edges neatly, creating a continuous barrier.

• High-temperature spray glue: Keeps foam and fabric firmly in place, ensuring they don't peel off when the metal heats in the sun.

• Expanding spray foam: Ideal for filling tiny gaps and sealing awkward corners where other materials can’t reach.

What tools do I need for insulating a van?

• Sharp utility knife or fine-toothed saw for cutting rigid boards.

• Heavy‑duty scissors for flexible materials

• Measuring tape and marker

• Safety gear: Gloves, eye protection, and a mask for dust control

• Screwdriver or drill to remove existing van fixings

How to insulate a van step-by-step

1. Preparation

Getting the van ready is the first step of a successful insulation project. This involves stripping everything out and cleaning up so you have your blank canvas to work with.

Step 1: Strip out the interior

Remove everything inside the van, including furniture, fixings and any built‑in units. Working with an empty shell gives you full access to every surface and makes the job far easier.

Step 2: Remove the floor and wall panels

Lift out the existing floor completely, then remove the existing wall panels and any trim pieces. Store screws and clips safely because you’ll need them later when refitting. Work carefully to avoid bending panels or damaging fixings.

Step 3: Clean the metal surfaces

Once the panels are off, you’ll see the van’s bare metal. Clean it thoroughly with a degreaser or a vinegar solution so adhesives bond properly. While cleaning, check for rust and treat any patches before moving on.

2. Insulating the floor

Once you van is completely stripped, cleaned and prepped, you can now begin insulating the floor.

Step 1: Apply sound deadening mats

Start with the bare metal floor. Lay butyl‑based sound deadening mats across the panels to reduce vibration and road noise. Press them firmly using a roller or squeegee so they bond completely. You don’t need to completely cover the floor, but about 50-70% is enough to quieten the van.

Step 2: Fit wooden battens

Next, create a framework for your insulation boards. Fix wooden battens directly to the floor using screws and adhesive where needed. Space them evenly so they support the boards and provide fixing points for the plywood layer later. If you plan to run electrics under the floor, you could leave channels for wiring.

Step 3: Install rigid foam boards

Cut your PIR foam boards to fit snugly between the battens. A fine‑toothed saw or sharp utility knife works well for clean cuts. Push each board into place and seal any small gaps with either roll insulation or expanding spray foam.

Step 4: Add a vapour barrier

install a layer of reflective foil (e.g. foil-faced bubble wrap or multifoil) over the insulation and battens. This will act as your vapour barrier to prevent condensation from reaching the metal. Ensure all seams and edges of the foil are completely sealed in place with aluminium foil tape.

Step 5: Finish with a plywood subfloor

Finally, screw plywood sheets onto the battens to form a strong subfloor base for your chosen floor covering. Once this is down, you’re ready for vinyl, carpet or whatever finish suits your build.

3. Insulating the ceiling and walls

These areas make the biggest difference to temperature control, so take your time and work methodically.

Step 1: Apply sound deadening mats

Start with the bare metal on the roof and wall panels. Just like the floor, fit your butyl‑based mats to large flat sections to reduce vibration and road noise. Press them firmly with a roller so they bond completely. Again, you don’t need full coverage, so place it strategically.

Step 2: Build and install your plywood framework

Fix wooden battens to the walls and ceiling where you plan to attach cladding later. Secure the timber to the van’s metal ribs using self‑drilling screws. Space them evenly to create a secure framework for insulation boards and future panelling. Leave gaps for wiring runs and ventilation points so nothing gets blocked.

Step 3: Fit rigid foam boards

Cut PIR boards to size for the ceiling and main wall panels. Push each board snugly between battens and seal any small gaps with expanding spray foam.

Step 4: Fill cavities with flexible insulation

For awkward spaces and ribs, use wool insulation or Thinsulate. Tuck it in gently without compressing it, as squashing reduces its effectiveness. For any smaller gaps where flexible insulation won't fit, you can fill with expanding spray foam.

Step 5: Add a reflective foil layer

Cover the insulated surfaces with a reflective foil or multifoil for your vapour barrier, sealing the seams and edges with aluminium foil tape to create a continuous layer.

Step 6: Refit the van wall panels

Replace the van wall panels using the original screws and fixings once the insulation and vapour barrier are in place. Make sure each panel sits evenly and is firmly secured.

4. Insulating the windows

Windows are the biggest source of heat loss in a van. You can’t fill them like a wall, but there are smart ways to keep warmth in and condensation out. One of the best solutions is reflective foil mats. These mats are usually thin rolls of foil filled with bubbles, like bubble wrap, or microfibre. They’re lightweight, energy‑efficient and easy to handle.

Ideally, you want reversible mats with one reflective side and one dull side. The shiny surface reflects light and heat, while the dull side absorbs it. This means you can flip them depending on the season or your preference.

For a more permanent option, you could use foil tape around the edges. It might look a little rough, but it blocks every crack of light. Simply covering the windows overnight makes a big difference, both for keeping heat in and shutting out light.

Extra van insulation tips

Wrapping your van in insulation keeps it warm, but good ventilation is just as important to prevent condensation. Aim for at least one air inlet and one outlet so fresh air can circulate. This could be a roof fan paired with a sliding window, or even a discreet floor vent that draws in cool air from beneath the van during summer. For damp winter months, a compact dehumidifier is another smart option to keep moisture under control.

This is a marketing article from Howden Insurance. The information in this guide is intended for general guidance only and is accurate at time of publication.

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