Additional Thermal Insulation

We use our Kemerton all year round without any problems but find the rear shower room is consistently 4 or 5C cooler than the rest of the van in cold weather.  Draft-proofing the central vertical area of the rear doors has helped, and I recently plugged a howling gale coming through the gap between the two floors at the base of the doors.  Prompted by several comments on here about poor insulation I’ve now added more to the rear of the van. 

I found that AS had fitted the bare minimum, with many voids in both the doors and in the rear quarter panels.  These areas and also the side sliding door swallowed a 5m x 1m roll of 50mm thick automotive insulation without me having to stuff it in hard.  

Based on this experience I can imagine there’s scope for more insulation to be added elsewhere but access is impossible without deconstructing the shower room.  As always it’s a compromise.  I now need to get more heat into the shower room and hope that the roll of additional insulation will help keep the warmth in.

Tim

Hi Tim,
We also found the insulation lacking to the rear and sliding doors and like yourself managed to fill the rails and stiles of said doors with copious amounts of insulation hoping it would help. 
Unfortunately all internal steel walls are connected directly to the outside skin via steel spacers ( no thermal breaks ) as you would have seen when filling your doors. This I realised when after filling my sliding door with extra insulation and then sleeping in the door side bed I turned over in the night to be woken by freezing cold steel on my shoulder. The offending middle rail has now been covered with fabric.
Apart from eliminating draughts I think the only way to keep the van warm is via heaters and with most of the heat directed to the front and also if you keep the connecting door closed then the rear of the van is bound to be 4/5 degs cooler. Not sure what can be done about it except grin and bear 

Cheers Windy

When I bought my (non-A/S converted) panel van conversion 6 years ago, I asked the converter about adding extra insulation because I was a bit underwhelmed by what they had installed. Their response was that you should never completely fill a void between outer and inner skins.

They said that their installation was specifically designed to leave a clear vertical space on one side of the insulation, within the cavity. The purpose of the space was to allow convected air to circulate and carry away condensation that would otherwise accumulate on the inside of the outer skin, resulting in a risk of corrosion from the inside of the vehicle outward.

TBH I didn't think that the risk was a particularly large one, especially on a Transporter where the panels are galvanised - but I chose not to risk it, so it still has the same amount of insulation that it left their factory with!

That is my understanding also Roopert. 
I did a self build on a VW T5 back in 2012 and the general thinking on the VW forum (and there were many many threads regarding insulation) was exactly as you mention.

Thanks for the remarks and I agree about the need for convection space to reduce the risk of condensation problems.  I judged that in the case of our van the spaces left for such a purpose (assuming that was AS’s intention) were simply too large, and that the balance between adequate insulation and convection space was all wrong.  

Time will tell whether it was a worthwhile modification.  Overall though, and rear shower room aside, we have found the van to be sufficiently warm in cold weather conditions and are happy to use it throughout all seasons.  Not sure we’d take it to the Alps in winter though, even if we had the right tyres!

Tim

Although I commented above about not filling the voids completely with insulation, I have to agree Tim that A/S insulation has generally been pathetic in the areas that I have investigated.
As you mention, time will tell but like you I’ve added a bit more in many areas of my van.

Roopert wrote:When I bought my (non-A/S converted) panel van conversion 6 years ago, I asked the converter about adding extra insulation because I was a bit underwhelmed by what they had installed. Their response was that you should never completely fill a void between outer and inner skins.

They said that their installation was specifically designed to leave a clear vertical space on one side of the insulation, within the cavity. The purpose of the space was to allow convected air to circulate and carry away condensation that would otherwise accumulate on the inside of the outer skin, resulting in a risk of corrosion from the inside of the vehicle outward.

TBH I didn't think that the risk was a particularly large one, especially on a Transporter where the panels are galvanised - but I chose not to risk it, so it still has the same amount of insulation that it left their factory with!

Plus one for that. My first thought was that filling voids between steel panels with insulation is asking for condensation on the steel and subsequent rot.

Spray foam insulation directly onto the steel is widely used on steel boats to good effect but I'm not sure how practical it would be as a retrofit on a van.

The big difference there would be the thickness of the steel involved. You can afford to lose (and probably expect to lose) a fair bit of the steel on a hull to rust. But you can't on a van!

The application of expanding foam on vehicles is something that is almost universally regarded as a bad thing to do - for more reasons than just corrosion.