Airbrick and damp, 1890s house

16 Dec 2016
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United Kingdom
Hi all,

I have an issue with damp in my kitchen. The wall is an external wall, and looks wet. It has an airbrick that’s been added later, which is just in the outer leaf.

I’m thinking of removing this airbrick as I don’t believe I need to vent the cavity? And also I’m thinking of adding a French drain along the wall?

It’s a 1890s terrace, the pipe you can see is just the boiler condensate pipe. I’ve attached some photos -


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Are the two middle pics showing damp in the kitchen?
Stand back for a context, & better, more clear pics of the internal damp?
The amount of green algae suggests that water could be cascading from the roof or the gutters?
The air brick is useless. So is the failed attempt at pointing.
Remove all debris and grime from the gully trap, and empty of water, and then dry out the gully - then look for cracks in the gulley.
Water shouldn't be streaming down the wall. Find the water source and stop it there.
Looks nasty. More investigation needed before you decide on a course of action.

I'd start by hacking out all that hard mortar pointing to see if there is any form of dpc there?

Why would somebody add a vent to a cavity? In older houses it was common to have vents - one high, one low, - to a pantry. Could it be an old pantry vent that has been blocked up inside?

Are there any other vents around the house?
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You evidently have a severe and long term source of water.

Stand back and take some wider pics. Show the entire wall, all the way up to the gutters, and all the way down to the drains.

The pipe you show is unusually big for a boiler condensate pipe. Does it discharge onto the paving, or is there a drain? Glazed clay gullies and drains are almost invariably cracked and leaking, and newer concrete around them usually indicates a futile attempt to hide (it does not repair) the fault.

How old is the house? Can you see the original DPC anywhere round the house?

Do not allow anybody who sells silicone injections near your house.

I see 1890's. So it might not have a DPC, but quite probably it has a slate one. They were compulsory in London from 1875, other towns vary. And at that age I'd put money on broken gullies. Since 1940, and leaking ever since.
Last edited:
Hi, yes the two middle photos are the internal side of the same wall.

The pipe goes into what looks like a drain but it’s filled with gravel? I’ll start to empty it to investigate.

I’ll take some more photos, there is a gutter high above the wall. Maybe that’s leaking?

Removal of the airbrick would be a good idea then?
That's not your top priority.

Fix your drainage problem.

I don't doubt you will end up digging out the broken gullies, but by all means explore other possibilities.
Ok thank you, so it looks like a combination of water running down the wall and a broken gulley?
Haven't seen enough pics yet, I don't know about water running down the wall. Drains should not be blocked with gravel so clear it with a long spoon and see what you find.
I can see green and wet bricks at and near ground level. I can't see signs of water running down the wall.
The mortar and brick above the vent is wet. Looks too high to be rising damp. Can't see how the water jumping across the vent to get to the area above. The water most likely come from above. A photo covering a larger area above the vent could help with the assessment.

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