Water staining around chimneys

I've recently purchased a property that exhibits water staining on the walls either side of both chimneys, as shown in the attached photos, along with some drone shots showing one of the chimneys from different angles. This issue wasn't visible on any of the survey photos that were taken in November, however, the UK has experienced some record rainfall since then.

I've contacted various roofers who have given different explanations and widely varying costs to resolve. I'd be very grateful for the thoughts of the roofing experts on this forum.

Many thanks.

The chimney stack is unusually large, and the lime bloom indicates a lot of water getting into it, this seems to start above the roof line. So I would have thought it was rain getting in the top. I do not see a photo of the top.

The visible leadwork looks OK so I wouldn't have thought it was the roof/chimney joint, such a bad defect might be quite big. Have your roofers climbed up and examined the top and the leadwork?

There is a faint chance there might be steam or water getting into the chimney, from a bathroom extractor, gas appliance or plumbing leak, but that seems unlikely, unless the chimney had been blocked and then used again.

Are all the flues ventilated top and botom? This is necessary to dry them out.

Thanks very much for your reply. I should add there's no sign of water ingress inside the house. I've attached a couple of photos of the top of the stack.

I think the flaunching has some cracks that will be letting rain in, and the upper brickwork is very poor and losing mortar. I see the pot has been closed with an "elephant's foot" which allows a little ventilation, but I think more rain is getting in.

Is the chimney now totally disused, and does it have a vent at the bottom?

As the brickwork at the top is in such poor condition, I'd lean towards having the old brickwork taken down until you reach the sound part, then maybe capped with a precast paving slab or similar (these are much more resistant to rain and weather than mortar flaunching or bricks) with an airbrick at each side for ventilation.

As the problem is the chimney rather than the roof, a reputable local chimney sweep is likely to know the local people capable of doing a good job on it. He could also advise on how to leave the chimney in working order, in the event that you want to put it back into use. Make it clear that you are happy to pay for his expert advice.

P.s.

Looking at the brickwork, the upper metre or so looks like it is different, either a repair or to increase the height. There's a possibility that it might not be as well-built as the rest of the house.

Or maybe it is just long term water and frost damage.

Thanks for your further response, I really appreciate it. The brickwork at the very top of the stack is a different pattern, which I don't think was clear in my previous photos (I've attached a clearer shot below). Also, as noted in my original post, I have an identical chimney on the other side of the house which is showing similar staining on the walls, but not as bad.

Of the two chimneys, one isn't used, while the other (the one you've seen the photos of) has a gas fire, but the flu for this seems to exit about halfway up the chimney, as can be seen in the ground level square on shot from the original photos I posted.

The suggestion I had from one roofer was that the tray/DPC should have extended to the front face of the chimney and overlapped the face by a few inches. The suggested solution was therefore to dismantle the chimneys to the tray height and redo the DPC and the tray, then rebuild the chimney stacks to current height.

I think you need to verify that the gas flue is not leaking into the chimney. Burning gas generates a lot of water vapour.

MaveUK said:

I've recently purchased a property that exhibits water staining on the walls either side of both chimneys, as shown in the attached photos, along with some drone shots showing one of the chimneys from different angles. This issue wasn't visible on any of the survey photos that were taken in November, however, the UK has experienced some record rainfall since then.

I've contacted various roofers who have given different explanations and widely varying costs to resolve. I'd be very grateful for the thoughts of the roofing experts on this forum.

Many thanks.

Click to expand...

On the chimney, I am seeing what appears to be - the water stain appearing out of what looks like two drains on the chimney face side.

In your final photo, below the eaves and gutter, I am also seeing a much wider area of water staining, on the wall either side of the chimney, which you seem not to have mentioned in your post - It is very obvious in the final photo, of your original post, which is copied above.

Harry Bloomfield said:

In your final photo, below the eaves and gutter, I am also seeing a much wider area of water staining, on the wall either side of the chimney, which you seem not to have mentioned in your post - It is very obvious in the final photo, of your original post, which is copied above.

Click to expand...

It's not coming from the gutters, is it?

Harry Bloomfield said:

On the chimney, I am seeing what appears to be - the water stain appearing out of what looks like two drains on the chimney face side.

In your final photo, below the eaves and gutter, I am also seeing a much wider area of water staining, on the wall either side of the chimney, which you seem not to have mentioned in your post - It is very obvious in the final photo, of your original post, which is copied above.

Click to expand...

Thanks for your reply. It’s the water staining on the walls of the house either side of the chimney that is my main concern.

I believe the guttering and down pipes are clear, so assume the water ingress is coming from some other source. However, I did wonder if during a particularly heavy storm the water hitting the back of the chimney is overwhelming the gutters, but we’ve not had any very heavy rain for a few weeks where I am, and yet the walls still haven’t dried.

OP,
Your "main concern" appears to be caused by the stack details.
1. The flaunching, and stack top to below the decorated brickwork or even down to the lead DPC tray will need removing and rebuilding with new bricks.
2. The new flaunching must have a smooth finish & all round projection of, say 20mm to 25mm.
3. The flashing is wrong - it should be stepped cover flashing over individual soakers for those tiles.
4. Most important: the flashing must peep over the gutter - not stop short.
Kick out diverters might also work?
5. At present water is going under the flashing & penetrating across the soffit to go behind the fascia to soak the outer skin brickwork below.
The back gutter & other flashing could also be allowing water in?
Both fascia's are looking a bit worn?
The soffits are well served with ventilation.
6. Both (different type) gutters are holding water and debris - perhaps their falls need adjusting for a free flow? The gutters might be allowing overflow & splash?
7. The whole back gutter needs reconstructing - its ponding - it seems a bit odd below the immediate course of tile above the BG.
8. Have you been in the loft to investigate the loft chimney breast, & why all the venting? Check that there's a membrane below the tiles.
9. Has the fireplace below been blocked up?
10. If its posible to sweep when did you last have the flue swept?
11. The staining is, of course, Efflorescence - there are probably thousands of google pages suggesting how to deal with/clean up efflorescence - it will be your call after reading up a bit?

Some/most of what I've written will, presumably, work with the other stack?

JohnD said:

The chimney stack is unusually large, and the lime bloom indicates a lot of water getting into it, this seems to start above the roof line. So I would have thought it was rain getting in the top. I do not see a photo of the top.

The visible leadwork looks OK so I wouldn't have thought it was the roof/chimney joint, such a bad defect might be quite big. Have your roofers climbed up and examined the top and the leadwork?

There is a faint chance there might be steam or water getting into the chimney, from a bathroom extractor, gas appliance or plumbing leak, but that seems unlikely, unless the chimney had been blocked and then used again.

Are all the flues ventilated top and botom? This is necessary to dry them out.

Click to expand...

The fourth image especially, shows you may have a source of water leak somewhere - i.e. a pipe leak.

ree said:

3. The flashing is wrong - it should be stepped cover flashing over individual soakers for those tiles.

Click to expand...

I haven't made my mind up on the tiles. Are they a duo - Sandtoft or similar. The gauge looks to long for them to be plains. They may have gutters. ..Or might still need soakers too.

The Flashing is fine and correct for those interlocking tiles, (It could be a little longer to reach the gutter.) I see cover flashing and the bottom edge of a secret gutter which is good and correct
Check tile overlap onto the back gutter
The trays are doing what they should to a degree, But they are too small, the lower one possibly not turned up on the inside and sides.

not plain tiles fwiw

Thanks for all the replies.

I'm pretty certain it's not a pipe leak as there's no reason for there to be any pipes in that area, and, as mentioned, the second chimney has the same issue, albeit to a lesser extent. Similarly, the gas fire hasn't been used for years.

One further thing I did notice is that the lower set of weep holes appear to be blocked (photo attached)

I understand that I have far from a perfect chimney, but I'm still unsure of the smoking gun that's causing the level of water ingress on the walls that I'm seeing, especially as some of the comments above are contradictory (as has been the case when I've had roofers to the house to have a look in person).