John wrote:
I wrote a while ago about problems with damp coming into the house
where the new extension is. I've had a good look and can't see
anything wrong so I got a builder in. I thought he's going to be
expensive but he said it's basically down to porous bricks. The wall
is battered by the prevailing south-westerly and the rain just soaks
through. Not much but a little. He's seen it in lots of houses round
here. Is this likely? Can I really just fix the problem by painting
that weatherseal stuff on the wall?

Liquid Plastics K501 is not cheap but is brilliant for this:

http://www.liquidplastics.co.uk/product.asp?id=163

John