It’s gonna be cold out in the Gobi desert so I ‘m insulating the bug as much as I can. The bug has windows all the way around which I can’t do anything about but the roof, side panels and doors can all be packed.
I did quite a lot of research on insulation as it’s one of the most important parts of the conversion for me. by far the best explanation of how insulation works and how to find and use the best materials came from Greg Virgoe who is currently converting his Sprinter. Check out his video on the thermal properties of differing insulation types below. I didn’t go as far as to calculate my heat loss but I did use his advice when choosing my insulation.
I’m using all the insulating types as the bug is a funny shape and all the panels are different. It’s not as easy to get to some places as it is in a transit or VW van, I also can’t use Celotex on the side panels as they’re far too complicated.
On the roof I’m using 15mm polystyrene, I was going to use Celotex for this but polystyrene is quite a bit cheaper, is slightly more malleable, and still has good insulating qualities. I simply used spray mount to stick the polystyrene to the roof, do use it sparingly and keep the can a good distance from the panels as the glue will start to dissolve the polystyrene before the glue sets. I cut the polystyrene into sheets to make it more manageable, there’s quite a steep curve at either side so I cut thinner strips to bend around.
in the side panels, I’ve used earthwool type insulation to fill the panels as much as I can. The problem with the earthwool type insulation is that it has to stay dry otherwise it will rot rendering it useless and rather smelly. the panels are odd shapes so I cut out rough rectangles to fit and pushed them up inside the panels as much as I can to get as much insulation as possible. where I couldn’t reach I’ve used expanding foam to fill the gaps.I’ve also used expanding foam above the wheels arches I’ve had welded as there are a few gaps so this will help to plug those keeping my other insulation dry. The boot was easy enough like the panels however the other doors both sliding and front doors have winding windows which when wound down need space for the glass inside.
The sliding panels into the back of the van I’ve decided to remove the ability to wind the windows down. I figure that if we’re parked and too hot then we have 2 skylights to open and we can just open the doors if we want to. As there will no longer be back seats there will be no need to open the windows whilst were moving so seems like a sensible decision at this point. This has meant that I can use the earthwool insulation throughout the panel. The seals on the top of the windows were a little old and leaked so I’ve taken the quite drastic decision to silicon up the windows underneath the seals to ensure there are no leaks. The front doors I obviously want to keep the ability to wind the windows down so I’ve used what 15mm polystyrene I had left to fill behind where the window winds down whilst putting earthwool around the edges and along the bottom of the doors which seems to have worked quite well. I again had a few leak issues when looking at the window seals and also where the speaker cable comes through the front of the doors.
The floor in the back has 25mm polystyrene throughout. I’m installing a diesel night heater which has meant I’ve had to leave a section clear as it protrudes through the floor, I figure this isn’t much of a problem given that it’s where the heater is.
Over the top of all the insulation I’ve installed a vapour barrier to stop the water vapour in the air reaching the cold panels and condensing, this would make the insulation wet and eventually mouldy and would also mean my panels themselves would rust. As per Gregs advice, I’m using the foil covered bubble wrap as it will also give me a bit more insulation. I’m covering the roof, the footwells in the front and all the internal pillars. The only places I’m not doing is the doors, instead, I’m putting it on the back of my new door cards. This will mean that I’m likely to get some condensation on the outside of the doors but inside the panels will keep dry.
Finally, I’m putting carpet over the bubble wrap. As cool as the van looks covered completely inside in foil the carpet will provide me with a final layer of insulation and make the inside a bit comfier.
The difference is very noticeable from when I initially picked the van up and despite the good heater I needed to have it blowing full blast with my coat on the entire way home and could still feel drafts. Now I can comfortably sit in the van like I could any car.