What have we learned from our insulation guides so far?
Heat moves around our campervans in three ways, Radiation, Conduction and Convection.
Thermal bridges are areas where heat can transfer quickly, and need to be addressed in the insulation process.
Heat loss will occur through open space, through metal and glass. That’s the floor, ceiling, doors, windows, walls, ribs, vents and empty spaces.
For minimum heat transfer, we need to consider how we insulate all of these areas.
R Values and breathability are important. We want a high R number and something that doesn’t get saturated with water.
Insulation can be expensive, so we need to balance insulation properties with price to not blow the budget.
Rigid board, Reflectix (when used properly) and wool all look like they fit the bill.
To read more about insulation, check out our guide on ‘Campervan insulation’.
How do we fit insulation in our campervan?
Casting aside complexities, the easy answer is to say as you get as much as you can fit in the space.
You’ll see from the heating options, it’s going to be much better to spend a bit extra cash and time on this step than having to upgrade to a better heating system, or (eek) aircon.
Insulating the van is actually a relatively simple job of few parts, but it does take some time. And it is boring. It’s very easy to cut a corner here because you never get to see any of the insulation. Especially if you are intending on selling the van after a short trip. Please don’t skip corners here.
When you are in the van, you will not regret this.
Insulating campervan floors
For the floor; we’re going to use thick stuff; rigid extruded polystyrene insulation. In the UK the two brands are Kingspan and Celotex, they’re basically the same. You buy them in the same place you get wood – the builders merchant. It’s actually a fairly simple job and one that comes together quickly once you find your rhythm.
If you’ve been following along, you should have a layer of Reflectix on the floor. On top of which you have screwed batons into ribs to create a framework.
You now need to cut the XPS into the (likely) rectangle gaps that are in between the framing.
You can use anything with teeth to cut Kingspan, a wood saw will do fine. If you have a ‘finishing saw’ that has a thinner blade, that will work even better.
Kingspan has a handy grid drawn on to it. You can use a piece of straight wood to run the saw along for longer cuts.
Install each panel one-by-one. You probably don’t need to do this, but you could, if you wanted, glue them in. Best to cut as close to fit as possible and squash it in a little.
Consider leaving a small gap around the walls of the van that you can fill in with some expanding foam. XPS will squeak, which might get annoying when on the road.
Then, cover the whole lot with Reflectix, creating an insulating sandwich. Reflectix -> framing and XPS -> Reflectix.
Install the subfloor, using as few screws as possible. [more on subfloors here]
Insulating the walls
On to the Walls. Same principle, you’re going to make a Reflectix Sandwich. This time you won’t have any Relectix on the walls, so we’ll get that layer on first.
Cut your Relectix to a reasonable size for you to work with. A Stanley knife cuts through this stuff really easily. I wouldn’t recommend trying to stick more than 1.5m at a time, it gets too hard to align.
Make sure you have removed everything from the van you don’t want to get glue on, and ideally do it on a warm day, when you can have the windows and doors open (for ventilation).
If you are using Spray foam, spray in all the empty spaces and columns to fill the gaps. If you aren’t stuff your plastic wool into as many gaps as you can see. Be very generous. Use a screwdriver or something similar to stuff wool into places you can’t reach with your fingers. Next, fit Relectix.
Spray the wall you want to add Reflectix to with contact adhesive.
Spray the Reflectix with contact Adhesive.
Let each go tacky, should take about 60 seconds.
Stick the Reflectix onto the wall.
Start inside the panel and work your way outwards.
When the whole van is done, you’ll have a spaceship looking interior. It’s time to move on.
Grab the plastic wool and stuff it into the cavities.
Once you’re full up (from the bottom of the panel) just a stretch of duct tape from pillar to pillar to strap the wool in.
Next, do the top of the panel.
Plastic wool into all the cavities!
Next, get your contact adhesive back out.
Spray the columns (mostly) and the wool. Spray the Reflectix. Let it go tacky.
Stick the Reflectix to the wall, to create the sandwich effect. Reflectix -> wool -> Reflectix.
Use the silver Reflective tape to cover the seams.
Framework for the walls can go on top.
Tips: cutting the silver tape with your teeth does not work. Best to have two hands on the job and use a blade to cut. If you are running out of tape you can cut it in half – lengthways – to get twice the amount of distance.
Make sure you remember to mark off where anything important is, like struts/ framework, and cut and pull through wires for sockets etc.
Insulating the ceiling
The ceiling is much the same as the floor, or the walls, only a bit harder.
If you are using XPS, you’re going to need a framework up, and to stick the insulation to the roof using plenty of contact adhesive, or these little pin things you can buy from the merchants.
If you are putting wool up there, you can spray contact adhesive on to the first layer of Reflectix to help stick it up, or consider putting lines of duct tape up first, that you then stuff the wool above. Or, you could use a mold resistance nylon to create lines that the wool will sit on before you stick the Reflectix. Same thing.
Remember that heat rises, so if you want to keep the warmth in, the ceiling is the most important part of your insulation. If you can figure out installing XPS, and you have the head space to lose, it’s the best way to insulate.
And then
Fill gaps with Spray Foam Insulation. Not much instruction here, just stick it in the gap and spray. If you are doing this for the first time now, spray a little as a test somewhere, to see how much it expands.
Trim excess foam with a utility knife.
What about the cab?
If you have removed the bulkhead you might want to consider re-insulating the cab too.
First you need to remove the hard fabric/ plastic attached to the ceiling above the cab. It’s usually held up with a few clips.
Stuff wool into all the gaps between the ceiling above the cab.
Clip the fabric back into the ceiling.
Great Stuff gaps and cracks spray foam is useful for filling odd shapes and gaps in the van.
It is important to stuff these areas with scrap foam and avoid compressing the fibre insulation too tightly.