Hi
Looking at a caravan on e.bay,one of the pictures shows blistering on the shelf under the front window,spoke to seller they said either condensation or sun damage,does that sound right?
If its on the shelf it could well be sun damage but if on the wall it sounds like damp.Agree with Oxter if thinking of buying take a damp meter in fact, take a damp meter no matter what van your thinking of buying..
Yep - it's an investment for caravanners. Great if looking / buying but use regularly on current 'van to spot problems early before they become big problems. I got mine years ago at B&Q and have used it extensively to good effect. Not as sophisticated as the dealers' meters - but ticks all the boxes for amateur use.
It could be sun damage, but if you go to look at the van and you haven't got access to a damp meter, try and see the shelf from inside the gas locker. Sometimes the manufacturers leave the timber exposed and if the timber has turned dark then it is damp and would need replacing.