I live in a terrace property and have had a damp problem in this area for over 10 years which started off as a very, very small patch but has grown over time. When it first appeared I had various tradesmen giving their views and remedial work undertaken which included renewing of lead flashing of the chimney where it meets the roof, waterproofing agent painted on the chimney wall on my side. And the repointing of the chimney wall on my side. Nothing seems to have really helped.

I will attach 4 pics to show:
1) The relative position of the patches at ceiling level, and thru the roof access and the velux window in my roof, and partial view of my neighbours' chimney above the roofline.

2) A close up of the damp patches.

3) The brickwork inside the roof area just above the ceiling line. On investigation today there appears to be a pile of red dust, inside the roof area, just above the largest damp patch as well as streaky lines on the brickwork. These looks to be ominous if revealing signs?

4) The chimney breast thru the velux window.

From picture 3, I suspect that due to the crumbly look of the pointing and bricks this might indicate that water is leaking/seeping in (from the chimney wall)? Can anyone please advise if my suspicions are in the right direction and what remedy to take? For instance, if the brickwork is repointed, below and above the roof line, will this stop the water "settling" to finally appear as the current damp patches. Any other opinion would be much appreciated.

Incidentally I don't notice any more damp when it is raining than when not other than maybe the water is possibly being absorbed in the brick over time.

Thanking you all in advance.

The brickwork above the ceiling looks dry from here (hard to tell on computer)

Is there a fire in the chimney breast and is it still used?

It could be a couple of things causing this, but it's hard do diagnose the exact fault, so here are my thoughts-

* There could be something in the chimney, which is creating a cold spot on the wall and condensation is forming in that area.
** The chimney pots might not be suitable and could be damaged allowing water to build up on the inside of the chimney.

If it was my house I'd remove a brick from the brickwork above the ceiling and see if you could see something obvious, perhaps even hire an inspection camera for the day (one with a good light on the end)

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DIY | Donnas dream house

It does look like water does run down that wall below the Velux. Have you had the leadwork checked by someone other than the guys who put it in? Could be fine, but that's first place to look I guess. Also, I don't suppose the problem has been since Velux went in? - lots of installers make a hash of the flashing on these - it also looks really close to the abutment with the wall, so I'd check that's all ok. At least having the Velux there, makes it easy to have a look outside!

Sorry jadeylady - fat lot of use we are

I see what your saying UHM with it being dry, but do you think it shows that water does sometimes run down the wall?

I see what you are saying too, but thought that might of been from before the flashing was replaced as it looks dry

I suppose a damp meter would be handy as the brickwork above the ceiling could be checked to see if it is damp or dry

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DIY | Donnas dream house

I'm curious about those spalled bricks and the dust beneath them in picture 2.

Is the chimney still in use and/or when was the last time it was swept?

Makes sense, but if that was the problem and its cured, then why still damp (just made me laugh as we posted at the same time saying completely opposite things ) - which suggests that it could be chimney issue as you suggest Good shout on the damp meter.


Agree - maybe when builders looked at the problem - they had a good scrape to look below the surface as it were?

Thank you all for your advise. Here are my answers in no particular order:

* The velux was installed since the damp started to appear so I don't believe it's caused the problem. It was installed so that jobs in the roof like this can be gotten to. I've had other people in since the flashing was replaced and no one seems to think it was badly done.

* Unfortunately the chimney's my neighbours so I don't have any access to it or able to do anything from their side of the party wall. I've spoken to them but not very helpful. I can't replace the caps either as they're not mine!

* The wall feels very very crumbly to the touch. Can this be caused by water ingress?

* Although the wall inside the roof area has the streaks I've never actually seen water running down it! I was hoping someone might advise me what the streaks might be. Does the white in the streaks indicate lime? Although that still doesn't tell me where the water is coming from other than maybe it's permeating from the wall but the runny appearance gives indication of the seepage moving downward somehow.

* Does anyone know why the brick appears crumbly, is it just old age? These are properties built in the 1890s!

* I guess a damp meter is a good way of checking it.

Julian Cassell wrote:
I see what you are saying too, but thought that might of been from before the flashing was replaced as it looks dry


Makes sense, but if that was the problem and its cured, then why still damp (just made me laugh as we posted at the same time saying completely opposite things ) - which suggests that it could be chimney issue as you suggest Good shout on the damp meter.

dextrous wrote:
'm curious about those spalled bricks and the dust beneath them in picture 2.

Agree - maybe when builders looked at the problem - they had a good scrape to look below the surface as it were?

jadeylady wrote:
I'm curious too. No builder has been up there to scrape the brick internally and yet there's a pile of dust underneath gathering of it's own accord... what might that be?

Spalling tends to happen when water seeps into a brick and freezes, thus expanding and breaking the front layer off. Not really too much to worry about, especially in a house of that age. Nor is it unusual to find that the mortar is soft and crumbly.

It may well be that the whole thing is due to condensation on the brickwork in the loft as UHM suggests, but the problem only being 10 years old....? (I'd have thought it would have been around a lot longer)

I'm more inclined to go for the problem coming via your neighbour's side - it may need re-leading, or repointing, or indeed the flaunching around the pots may have finally given up the ghost. There are other possibly but less likely solutions, but that's where I'd be starting at.

Are you suggesting that at this point I don't need to consider repointing the brickwork in the loft but to concentrate on having the flaunching and fillets around the chimney pots redone? I'll need neighbours' permission but if they refuse is there something in the Party Wall Act that I can invoke to get the show on the road? One doesn't want to go down that route unless absolutely necessary...

Repointing internally may "plug the gap" and stop the water from working it's way through, but IMO it would be wiser dealing with the root cause. The problem at present is that the brickwork in your pictures don't clearly prove that that is where the water seeps through - it may well be the case that the real mischief is acually occurring behind the wet plaster patch itself. So, if water could be prevented from getting in in the first place, then that surely has to be a better solution.

What do your neighbours actually say?

Dextrous, I can't agree with you more that it's better to get to the root cause than to skirt around the issue. If nothing else it's very frustrating, time consumming and expensive trying this and that. The trouble is that when you get a trades person round they just want to give you a spiel, take your money and move on – you can never get them back. And with a problem like this it takes time to see a bit of result and I have tried 3 options as mentioned before. I was hoping that on a forum like this someone else has experienced a similar problem so that I can narrow things down considerably.

When I had the neighbour round it was a few years ago when the problem wasn't was as bad and he couldn't give me any reason that they've done anything on their side to have caused it. At the time I have no reason to suspect his chimney pots as possible culprits. Should I consider asking for vents to be put into his chimney breasts inside the house? Is that a request too far? Does the fact whether they use or don't use their chimneys have a direct effect on condensation? Obviously I'll need to have another word...but thank you for your thoughts.

One other thing if I may ask: Whether it's a condensation problem or water seeping in thru cracked flaunching etc, why it is settling/cropped up in that place where the damp patches are showing ie where the wall meets the ceiling and not further down the wall in the landing for instance?

If they have blocked up a disused chimney inside and not allowed airflow through it, then any water that gits inside (via rain) will be less likely to dry. Second, if they have a disused chimney that has become blocked up (fallen bird's nest, internal brickwork collapse etc etc) then you have a similar situation. Hence my questioning about the current status and usage.

Suitable cowls can be used to prevent rain from falling through the pots, at quite reasonable prices and access is simple enough to put them in place via your velux as a diy project. While someone is up there they could inspect/repair the flaunching at the same time, so at least this wouldn't be a costly project and would eliminate a couple of possible causes.

Regarding your question of "why there", in simple terms ... "who knows?". Flippant answer maybe, but an honest one It may well be the simplest place for this water to "escape".