Hi All ,

I am in the process of lining and insulating my new swb med roof transit and I am really trying to get it right however I would very much appreciate comments and advise as this is my first time.

I have 6 mm ply lined the van and now intend insulating so it can be used during the winter in the alps with the addition of a Eberspacher diesel heater. My intention is to line between the body and the ply with Celotex/ Kingspan foil covered stuff  and my concerns are whether it is necessary to install a polythene membrane over this or not. My thoughts are that if a membrane is in place and vapour manages to get trapped it will remain damp and cause problems. Actually fitting a 100% vapour barrier looks very difficult.  Another thought was to insulate without the vapour barrier and on return to home run a de-humidifier in the van for a couple of days to thoughly dry things out.

My choice of Celotex/ Kingspan is that it will not sag or actually hold water itself.

Any comments or experience would be very welcome.

Regards

Lincol