there are some great expensive sound deadners out there...
but I used the blue YOGA mats available everywhere for $5-95
PVA waterproof - I used two layers on the roof of My beetle
also in doors rear trim... around the engine bay- everywhere...
I used contact cement- coat both sides - foam and roof..
wait until touch dry then press them together...
don't make a mistake as you will never get them apart..lol
I also did above my gearbox etc...
My beetle is never really hot inside and the reason is the PVA foam.. as the roof never gets hot inside...
there is better stuff.. foam with silver foil attached... but very pricey... but Your Kombi will be like a Mercedes... lol
cheers
LEE
PS: spray expanding foam into places you can;'t get to...
LEE
- Helping keep Air Cooled VWs on the road - location: SCONE in the Upper Hunter Valley - Northern NSW 320 kms NNW of SYDNEY---