Just rebuilt chimney & it’s still leaking. we had it brought down into the house rebuilt, reflashed and re-roofed around the flashing area. As well as the roofer was to put down a rain and ice barrier. It’s been raining yesterday & today & we found it is still leaking…much better but still water is getting in

Any thoughts on why the leak?

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  • 2
    Porous masonry was the primary issue I encountered after the flashing issues were corrected. Sealing the chimney is now on the list for every three years or so. That also involves checking for gaps between the flue pipe and crown and sealing any cracks in the crown. The cap on your chimney is quite different, but windblown rain will still get in.
    – HABO
    Oct 31, 2023 at 3:15

3 Answers 3


I'm judging by fuzzy photographs, but the flashing seems to have been done incorrectly. When done right, shingles and step flashing alternate such that any water running under one is still on top of the other. Here we see very large metal flashing laid completely over the shingles, so that any water running or blown under the metal encounters no further drain plane beyond the edge of the shingles.

Here's a diagram of where I'd have expected the shingles to overlay the metal (and lay under the flashing above):

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Here's a good example of proper flashing:

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There's also a diagram of the step flashing on that article.

I can't be sure this is the problem, and I'd hate to accuse your tradesperson of negligence, but that's where I'd start. Read and understand that article, then compare your situation.

  • 1
    This is a good example of why people need to make sure they hire people/businesses who are licensed, bonded, and insured. Not only does it help make repairs of repairs simpler, but it also helps ensure (but not necessarily guarantee) that the people doing the work are sufficiently trained so the repairs won't need repaired. Hopefully this isn't a "fly by night" operation with the OP needing to pay someone else to fix this shoddy work. Oct 30, 2023 at 23:25
  • I'm not 100%, but I actually think this is an example of not-great flashing. As far as I'm aware, long before shingles/tiles are involved, the flashing should be mortared into the brickwork (in the picture, you can see the pointing has been raked out, possibly to facilitate this, or possibly to remove the old flashing). Once the flashing has formed an absolute seal between brick and roof, then the shingles/tiles go over the top as pictured. Here's an example: verticalchimney.com/blog/chimney-flashing Oct 31, 2023 at 15:15
  • I get you now. The top of the step flashing isn't integrated with the chimney in the second photo. One way I've seen that done is to have a full-length flashing lap over them and which is cut into the chimney on a straight line.
    – isherwood
    Oct 31, 2023 at 23:44

Isherwood is correct - this looks like very poor flashing. I would also add that the lead has not been well formed into the corner. If you are exposed to driving rain in high wind this would increase the chance of rain being blown under the flashing. It is also possible that if it has been built with very porous bricks, in prolonged very severe weather the bricks could be transmitting water through the wall. If that is the case a coat of weather-proofing should stop penetration.


Use chimney brick waterproofing spray or cream. It’s siloxane based. Use as described. It’s looks like your mortar is taking in water. That water gets behind the chimney flashing and behind the ice and water shield. Cheap fix and you should waterproof the chimney brick and seal coat the crown anyways to prevent issues. I mean dude you have moss growing out of it….

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