Damp - tried various things with different roofers, but it won't go away.

Hard to be sure without looking but as it occurs when it rains you can discount any notions of condensation. This is a leak! I suspect it may be the flaunching (the sand and cement capping/bed that usually holds the pots or closes a chimney off). If it was the back gutter you would expect to see a noticeable amount of water. Sometimes, rain gets into cracks or gaps in flaunching and runs down the inside of the chimney, then tracks into open joints. This is why it often shows as damp patches, because it is seeping slowly from the inside of the chimney out. Regards, Sean (Roofmonkee)

Does your roof have a high pitch ?the reason i ask is, if the pitch is very low its easy for rain to be blown up past the lead (if there isn't enough up stand) and then run down the chimney or a timber beam, usually on the last slate of the tray behind the chimney. If you don't use your chimney it may be worth taking it down ! Also do you know if the plaster board used has a foil back ? in high moisture areas moisture/foil back board should of been used and well insulated with celotex (gaps filled up with expanding foam. if any) The first place you'll notice condensation is on your windows so if your windows arnt covered in condensation when you notice damp walls you must have a leak somewhere. It could also be condensation of pipe work in stud wall cavities that havnt been insulated or even a small leak! (I'm guessing there is a rad in the room)! get your pressure checked in the plumbing and heating hope this helps in some sort of way :)

I have investigated and successfully dealt with hundreds of problem chimneys – usually within the private rented sector in my capacity as a surveyor / damp-proofing plasterer, and roofer Issues with dampness around chimneys can be challenging. They are rarely straightforward and require a comprehensive investigation – internally and externally. A problem can be compounded when moisture from the atmosphere, whether being generated internally (such as condensation) or penetrating from the outside (faulty chimney details) can react with residues of fossil fuels within the chimney structure (soot, for instance, holds hygroscopic salts): this can lead to a chemical reaction occurring. This needs to be understood before any remedial treatment is proposed – otherwise you can be paying out time and time again. Internal damp patches around the chimney breast area may only appear when it is raining and this can lead to assuming that the problem ‘must’ be an external issue such as a faulty chimney capping, pointing, lead flashings or surrounding slates, But, (and this is important), when it is raining, and there is high humidity outside, there will also be high humidity within the property. This is where condensation comes into the equation and some internal remedial work is likely to be needed I have taken a look at your photographs. The quick answer to your questions is to remove the chimney completely (since not in use) remembering to allow sufficient slate overhang and to include an air vent brick which will prevent the redundant flue from condensing. The work can be carried out from the gable making it less costly. Problems that I see from the photographs with the existing situation are: Externally: 1. An improvised piece of lead attempting to channel water back onto the roof (this will sag in time, (if the winds do not dislodge it first). Water running down this area will cause a damp wall and a damp wall is a colder wall which will attract condensation. There may be external issues allowing water ingress if the wall pointing is defective too Removing the chimney will eliminate this issue 2. Ridge tiles have been used instead of cowls to allow breathing. These will allow the wind to drive water into the stack. They are also an excellent nesting place for Jackdaws … so thumbs up for the environmentally friendly approach  Removing the chimney will eliminate this issue 3. The capping – this needs to be done with a mortar mix suitable for chimney cappings (not the same mix as the pointing for instance). An overhang with a ‘drip’ would be best. Hopefully, suitable cowls would be installed at the same time. Otherwise, the weight of the ‘ridge’ cowls may weaken the capping – they should at least be properly supported. You will notice that your top course of bricks are beginning to fail already this is because they do not have the benefit of the old chimney pots holding it all together (the ridge tiles are a poor substitute) Removing the chimney will eliminate this issue 4. The chimney pointing is suspect. If it has been re-done, then hopefully the brickwork has been raked out to an appropriate depth and cleaned down before repointing with a suitable mortar mix. A quality and long-lasting silicone-based weather sealant could be applied to the brickwork afterwards to offer more protection (such as Stormdry from Safeguard) Removing the chimney will eliminate this issue 5. The lead-work has been trimmed into one continual piece. I would lift this up to check beneath. I would prefer that there were lead soakers placed beneath each slate separately. The existing lead-work has been pointed in with a sand / cement mortar mix. This will fail before long: lead expands and contracts with the weather – mortar does not and will crack. It would be better to point in the lead with either an oil-based mastic or a silicone based sealant (such as Leadmate). The lead flashing on the front chimney appears to be in two sections. It also appears that the upper section runs under the lower section. It is difficult to make out from the picture but if this is the case then this is fundamentally wrong – as with slates, they should overlap rather than underlap – that is why I would prefer to see lead soakers in place Removing the chimney will eliminate this issue If the chimney(s) are redundant as you indicated then I would suggest removing them. If not, then I would reconsider how the work has been done and how improvements can be made, based on the above observations. Whichever way that you decide there is still the internal issue to tackle because without dealing with the internal work then damp patches will more than likely still appear even though the external source has been rectified Internal remedial work is again based on an understanding of the reaction between moisture and fossil fuels and the principles of damp-proofing as applied to plastering. That is another chapter! All comments and opinions are based on my own continuing experiences and technical training. Individual cases may differ but the principles involved are similar Hope this is helpful, Regards, Chris

Hi Do you have an airflow in your chimney. Ideally vents should be fitted on the inside of the chimney breast and the chimney should not be completely capped off at the top to create an airflow. Also has the brickwork been sealed, sometimes the brickwork can become porous and soak in water this is easily solved by coating the entire brickwork with water seal. Hope this helps Thanks

Have you considered the bricks on the chimney might be soaking the water in like sponges and allowing it past the flashing? Try some external brick sealant

Hi Rossk, I have inspected your pictures, I guess you are having problems with the back chimney in picture 1...the flaunching is flawed, you can clearly see that the stepped (corbelled) brick closest to the roof has an exposed top edge, and wet joint, this will be the passage of the water, also what is the vertical slate/lead at the edge of the roof, back of chimney for/doing?? The vertical lead should not be there, I would advise you to take this stack below the roof-line and slate over. But make sure they install a 9" Square airbrick in the external wall to vent the flue, even if it's closed at the bottom (which it shoulsn't be) Regards Simon

All good advice from the replies above, you don't mention if the wet patches are on the high side of the pitch or the lower side. I suspect the causes have been mentioned above and all can be remedied but on the off chance depending how a roof has been felted the leak can be higher up and where the felts been cut around the chimney that is where the water is getting in. Check that there is coverage on the ridge and that the ridge covers properly, also check your pitch and tile gauge as someone else mentions back track. I assume that there is no hairline cracks on the tiles? Poor felting can direct water into an area where you then look for a leak only to find its actually higher up.

As suggested above it could be any number of things and chimneys are a regular weak spot. One thing is for sure like Stewart building points out and I remember having this conversation with old builder guy I know, that if the chimney is not capped and people don't light their fires any more they get soaking wet in winter but don't have the fire to help dry them. Solution, once a week you have a Charles Dickens evening, turn off the heating, turn off the lights. Light the fire and light the candles, kids love it.

Hi, Although people have mentioned that "if the chimney stack gets wet when it rains, it must be a leak", this is a very common misconception and in many cases the roof can be completely re-laid without ever solving the problem. The issue does look to be a condensation problem and is probably allowed to occur via convection (one of the three ways heat can transfer) if this is the case, the problem will be worse in heavy rain (especially a thunderstorm) where the differences between the windward and leeward pressures acting upon the building are so extreme. We have come across this issue time and time again, in many cases where roofers' will keep returning to add bits to the roof in the hope that it will resolve the problem. Roofers are, on the most part, extremely good at their jobs so if the problem was through rainwater ingression, they would have already resolved the issue. Please get in touch and we'll let you know some more about the problem and depending on your location (whether we can come and resolve it for you) we'll let you know how to stop the problem.