porous bricks

[John]

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?

Thanks

[stuart noble]

It's certainly a problem on SW facing walls in this area, but IME the clear seals aren't very effective. Are the bricks rendered/painted?

[meow2222]

Nearly every victorian house is built with porous bricke, yet most dont have a damp problem, and painting the ones that do with sealant only makes any damp worse. So I doubt both the diagnosis and the proposed solution.

NT

[John]

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

[John]

Ah, but.. it may well be true in our house. Thinking about it there was a small damp spot in the area where the kitchen and dining room join in the corner roughly where the damp spot is now. I hacked off the plaster and replastered it shortly after moving in and it seemed okay. However it may be that the damp is coming in through the cavity wall and is now being stopped at the extension and coming in through the ceiling. I could easily be talking b*ll*cks here though.

For the cost of "painting" the outside wall with waterproof solution and seeing if the problem goes away it may be worth a go.

The builder did tell me the flashing was very well done and if he wanted to make money out of me he cuold easily have recommended replacing it. This makes me (rightly or wrongly) want to trust him.

[John]

No rendering or painting. I don't particularly want to paint the bricks with coloured paint. I like bricks. I wouldn't want to render either unless I really have to.

[Rod]

But the real cost isn't the painting with waterproof solution - that is just a few pounds for the stuff. It's what you might have do if it either doesn't work or, far more significantly, it makes things worse. I doubt you can remove this stuff without the bricks. :-)

Perhaps try something like a sheet of plastic to protect that area of wall on a temporary basis to see if it helps?

[Bob Mannix]

Wise words. It will do exactly what the sealant will do (including any problems it may cause) but isn't permanent.

I always feel bricks are bricks and always have been and there's no need to go painting them. (Ditto plumbing compression fittings - they weren't designed for and shouldn't need anything else - maybe that's just me :o) ).

[stuart noble]

Absolutely, but often someone has already done that in a vain attempt to cure dampness. In that case your options are limited.

[Rednadnerb]

If it were caused by driving rain then the damp would appear only during a wet and windy spell and quickly dry out again. I had this problem on our west facing wall which is solid and fixed it by re- pointing and using the waterproofing stuff. I don't know how much each contributed to fixing the problem. What's the pointing like?

[The Natural Philosopher]

Its certainly possible but surely the wall has a cavity?

[The Natural Philosopher]

nearly ALL have a damp problem.

[Pete C]

Hi,

Could also be something like missing/defective 'cavity trays'

Try spraying the wall with a hose on a windy but dry day to see if the problem reoccurs or not.

cheers, Pete.

No damp means the problem is elsewhere.

[meow2222]

Sure, if you dont mind it making things worse. This is one of those very few topics where expertise is lacking here, I suggest you ask people that understand the principles in action and deal with this routinely.

The builder did tell me the flashing was very well done and if he wanted

=2E.. a salesmans dream

NT