Roof leak - chimney or skylight

29 Aug 2017
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United Kingdom
Hi, not sure if this is the right place to ask as it’s not really to do with DIY but just looking for some advice.

Three years ago I had leaks in the bedroom and bathroom. We had the skylight replaced (its seals were all rotted) and the bedroom dormer window re-flashed and re-surfaced (sorry hope that’s the right terms). All has been fine but I’ve just noticed a discoloured patch on the bathroom sloped ceiling which seems to be below the chimney (not used) rather than the skylight. I’ve attached a pic - the bathroom is on the left with the patch marked. Should I go back to the company who fitted the skylight to check it or does it look like the problem is definitely the chimney? Also if it is the chimney does the whole thing need reflashed and if so should cost be shared with neighbour?


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Cc246, good evening.

OK Sorry to say the posted image is not 100% clear but?

It appears that there are a couple of issues with the chimney stack.

1/. there appears to be a lot of "missing" cement pointing on the stack itself.
2/. From the image posted there looks like a "missing" area of lead? flashing at the base of the stack where it joins the slope of the roof on the elevation of the chimney stack directly facing the camera.
3/. it is not possible to tell if there is any lead? flashing on your side of the chimney stack.


A/. have the entire chimney stack raked out and re-pointed.
B/. Replace the lead flashing, I would suggest that the lead? be totally replaced, because if there is one bit missing the rest remaining may be in poor condition?

heres what i think i can see,

number one leak spot would be that small area at the very top of the roof join just below the stack, it looks suspicious?

the roof tiles are joined off-centre, thats if it is a bondin roof join -
plus thers no jointing strip showin?

the chimney stack base flashing is done wrong - but could be workin fine?
the stack seems to have a wonky flagstone cap covered with sheet lead - no flaunchin showin.
only one metal gas terminal showin. i'd imagine that thers four flues terminatin on top of that stack - all redundant fluesmust be swept an through ventilated.

both dormer flashins are done wrong as well but again, they could do the trick without leakin?

the velux type roof window is very tight to the ridge - too tight for good practice.
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sorry I just realised there were replies to this post - thanks very much.
We have not had any more signs of leaks since but I’m assuming left in that state it’s only a matter of time.
We spent £4K only 3 years ago (see original post) and I’m a bit annoyed the roof company didn’t notice the flashing missing etc on the chimney - would it be normal for them to check whole roof or just address the bit you actually called them about?
I don’t even know where this chimney goes, I can see any evidence of it in the actual house. My problem with getting it completely fixed is convincing the neighbour to chip in when he isn’t getting any leaks himself...
in theory is it possible to get the flashing repaired on ‘my side’ only? Have included another pic to show the right hand side of chimney, sorry hard to get a good angle because of the windows in the way.

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