How we built our camper van walls out of plywood
Most vans we have seen use timber cladding to line the walls and ceiling. This can look great, but we felt it was too rustic for the clean and minimal look we were trying to achieve with our van. Instead we opted for white painted 5mm plywood sheets fixed to the sides of the van. This was probably a lot more difficult than cladding would have been, but we love how it looks!
In short, we constructed the walls of our van as follows: We started our wall build up by attaching MDF strips to the metal structural ribs of the van, these would serve as the main fixing points for the plywood walls. Between these MDF strips and the voids within the metal walls we would insert 100mm of recycled insulation typically used in lofts. On top of this we added a layer of reflective foil insulation. Finally, we fixed on 5mm plywood boards with countersunk screws, cutting to fit around the vans irregular bumps. The plywood was then primed and painted!
The reflective foil insulation only really works as a vapour barrier in this situation. This type of insulation works by reflecting 'radiant heat transfer', meaning it needs an air gap in order to work properly. It's important to leave a gap between the main insulation and the vapour barrier to make it effective. To save some money you could also use a simple plastic sheet as a vapour barrier instead.
To maintain a continuous vapour barrier across our whole van, we attached the foil insulation to the floor and left some overlap to connect into the ceiling vapour barrier.
In our previous blog post about the floor of the van we mentioned the “skirt” of bubble foil insulation we had taped into the floor insulation, this is what we connected to and taped on to the inner face of the MDF frame.
The first thing we had to do was figure out where our MDF framing strips will sit. These strips were used to fix the plywood wall panels to the van’s metal frame. The MDF strips gave us extra depth so we can add the 100mm insulation within the walls and also reduces any thermal bridging created between the two layers. Ideally we would have created a flat frame to fix to, but if you do this you lose precious internal space as most vans have curved walls. This is why people use tongue and groove timber cladding or thin plywood as both options allow for some curvature in the van walls.
We had to cut the plywood sheets to size, keeping the width but chopping off some of the full sheet, we needed three sheets of ply for the side without a door and two for the side with the door. We fixed the plywood in place using lots of screws, countersinking the bits that would be exposed and filling them. The tops of most of the sheets would not be visible so we didn’t countersink these.
Once the plywood walls are in place and all screw holes and joints have been filled and sanded it's time to paint! We painted our walls with Farrow and Ball Wevet, found at Forest Recyling Project. The full tin of paint cost under £10, instead of £60, just because it was slightly dented! It's definitely worth checking if you have a reclaimed paint shop near you, as they can be amazing for small paint projects!
As you can see from our photos we had cables penetrating the vapour barrier, despite trying to tape these up as best as possible they will still be weak points. If we did this again we would keep all of the cabling within the vapour barrier. We might lose a bit of space, but it would mean that the cables would be easily accessible and that the vapour barrier would have less chance of failing.