Condensation problem... I think

Hi everyone... I have a 2005 TD5 truck cab (short wheel base) and I notice the lowest piece of the headliner (the long thin strip which runs horizontally below the bottom of the rear windows behind the back of the seats) was becoming very damp. It’s been raining relentlessly so I assumed I had I leak on one of the rear windows. I removed the headliner around the rear windows in order to see exactly where water was getting in then turn the hose on the windows from the outside only to discover.... nothing. To my surprise and despite training the hose on the windows for some time and from all sorts of angles I could make them leak. So now I am thinking maybe the dampness is a condensation problem.

I wondered what everyone else thinks and whether anyone has any experience installing insulation between the headliner and the surface of the car. If it is condensation, insulation is presumably the solution. Can anyone recommend any particular brands or products? I might replace the headliner at the same time. The bits i’ve removed in order to hunt for leaks look a bit grim and probably need to be replaced.

Camping mat is probably the cheapest, but the self adhesive neoprene sheets are very nice to work with, my only tip would be once it is all stuck up there run a bead of pu sealant around the edges to stop them peeling/lifting, messy stuff but real good gear, cheap enough from toolstation etc.

Thanks Lynall.... i’ve seen some self adhesive foil backed insulation specifically for insulating cars but it’s quite expensive and neoprene might be a good (and cheaper) alternative.

Jason Page said:

Thanks Lynall.... i’ve seen some self adhesive foil backed insulation specifically for insulating cars but it’s quite expensive and neoprene might be a good (and cheaper) alternative.

Click to expand...

Ebay closed cell foam is dirt cheap.

Jason Page said:

Thanks Lynall.... i’ve seen some self adhesive foil backed insulation specifically for insulating cars but it’s quite expensive and neoprene might be a good (and cheaper) alternative.

Click to expand...

I used quite a bit of the neoprene on a boat and it was easy to work with and also made quite a difference to the noise in the cabin, so it was win win.