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quigleybmd 09-18-2006 06:54 PM

water leaking through brick chimney
I have a relatively newly built brick chimney (about 4 years old),
and I get water into my attic during sustained rains.
I've also had the roof & flashing (embedded in the mortar) just redone, and my roofer believes the problem is with the chimney or crown. The chimney is large (about 3' x 6' x 3' high).
The brick/mortar & crown all seem to be in excellent shape, and there are caps over the 2 flues. But the crown is very level; there is no flashing between the crown & the brick; and the crown does NOT extend beyond the brick. I'm thinking of putting a new crown on top of the existing one, such that it does slopedown from the top, and extends beyond the brick. Does that sound doable?
Can I put a new crown on top of an existing one (there are no cracks or anything;and it's sealed with a product called 'Crown Saver')? Will it hold?
What kind of cement should I use to build it, and what kind of mortar should I use to attach it to the existing one? Also, anyone have experience with brick sealants, like DEFY Masonry Saver? The chimney was supposedly sealed with a product called 'Chimney Saver' when it was built, but now I'm wondering if some of the water is getting
in through the brick & joints. Any other suggestions would be greatly appreciated.
Thanks very much.

redline 09-19-2006 12:04 PM

Is the water leaking between the chimney and the roof?

or is the water leaking into the attic "thru" the chimney?


A photo would help

fqp25 09-19-2006 03:20 PM

A chimney cap is suppose to be made of concrete, not mortar.

Is there counter flashing installed where the roof meets the chimney?

Tscarborough 09-19-2006 04:14 PM

If you are getting water into your attic, the chances are that it is not an issue with your crown/brick/mortar leaking; each of those would present water at the base of the masonry stack (I am assuming that you have a masonry fireplace, not a zero-clearance one).

Most likely you have a flashing issue at the base of the chimney. Depending upon the location and rake of your roof, you may also need a cricket above the chimney. A picture or sketch is worth 1000 words.

quigleybmd 09-19-2006 07:10 PM

water leaking through brick chimney
In answer to the previous appends:
1. I believe it's leaking through the chimney (brick & mortar), and not the roofing/flashing. When the roof/flashing was just redone, they
put 'ice shield' on underneath the shingles & flashing.
But it's really hard to tell from the attic where the leaking is coming
from. The water just seaps out of the masonry block in the attic ..
some actually in the middle of the block!!

2. Yes, the existing crown is made of cement, not mortar.

3. Yes, there is counter flashing over the regular flashing. The
counter flashing is embedded in the chimney mortar, and caulked.
And the seams of the counter flashing are soldered (all copper).
And there's a cricket just behind the up-side of the chimney.

I'll try to get some pictures soon.

Thanks a lot.

fqp25 09-19-2006 07:34 PM

It is starting to sound like a liner problem.

redline 09-19-2006 07:50 PM

Can you see the water coming "thru" the bricks inside the attic or are you seeing water spots on the ceiling below the attic?

Do you have access to the attic?

Is the chimney located on the interior of the house or is it on an outside wall?

Does this have a clay flue liner or stainless liner?

Does the roof have a ridge vent?

Double check the cricket for leaks.

Does the roof have any other penetrations that water may leak thru that are within 15 feet of the chimney?

A roof leak can travel a distance making one think that the leak is in one spot but it could actually be in a farther different location.

What is the pitch of the roof?

When the leak appears, how much rain has fallen? (1/4, 1/2, 1, 2 inches..)

Tscarborough 09-19-2006 07:51 PM

With a masonry fireplace, there is no good way to seal the joint between the clay flue liner and the concrete/masonry crown (clay and concrete have different coeffeicints of thermal expansion, and having a fire in the flue excaerbates this effect). There is a proper detail for that joint, but it is seldom if ever used.

The crown should slope away from the flue liner, the flue liner should protrude at least 4" from the crown and the joint between the flue liner and the cap should be sealed with a flexible joint sealer.

Here is what a chimney cap should look like:

quigleybmd 09-21-2006 07:47 PM

Yes, I have access to the attic.
There is only masonry block there though. The brick work starts at the roof line.
I see the water coming in down the masonry, and a little right out of the middle
of the block (at a joint). There are rafters right against the block, so it's hard
to see above that.
The chimney goes through the middle of the house.
The flue liners (2) are clay. There are stainless steel caps over them.
There is a ridge vent .. within a few feet of the chimney.
There are no other penetrations.
I'm not sure of the exact pitch. It isn't too steep though; it's a single story ranch.
The leaking occurs after a lot of rain (more than 1 inch ... maybe even more than 2 in.).

The flues are > 4 in. above the crown. The whole crown and flue joint is sealed
with a crown sealer product.
I saw the Popular mechanics article; that's what I'd like to have done. Do I need to remove the existing crown??

I hope to have pictures this weekend.

Thanks again.

rredogg 09-21-2006 10:31 PM


There is a product I used with good results for chimney crown repair.
Its a latex product that you trowel over you existing crown and gives it a weather tite seal.
Its on the expensive side (container cost about 180.00) but there is enough product in the container to do at least 5 average size crowns. If you go in with neighbors or friends on the cost its well worth it.

Best of luck with the project, rredogg

Bonus 09-22-2006 11:58 PM

"There is a proper detail for that joint, but it is seldom if ever used."

Hope this isn't a hijack, but I'm always curious, and have been mucho impressed with other details you've shared. Do you have that in a format that you can post? Tks, Rich.

Tscarborough 09-23-2006 10:28 AM

The detail is from BIA Tech note 19b. There are 3 things noted that are seldom done:

There is no sealant bead around the flue.

There is no flashing/bondbreaker under the cap itself.

There is no overhang of the cap to prevent water from running down the chimney wall.

quigleybmd 09-23-2006 05:44 PM

brick chimney leak - pictures!! finally!
Here's a link to an album of pictures I took today.

The last 3 show the masonry block inside attic. You can see that it's damp from a recent rain. It's really hard to see much other than the exposed block, because of the rafter right next to the block. There's no water on the inside of roof on the other side of the rafter. I've taken off that paneling and looked.

Tscarborough 09-23-2006 05:54 PM

From those pictures, I do not see anywhere likely for a leak from the chimney. Is that a top of flue damper (the short one)?

The only possible place would be the cricket/roof valley. Is the cricket a later addition or original (it looks original)?

(Notice that of the three things I listed above, only the sealant around the flue is done, and it is an attempt to repair, not part of the original design)

redline 09-23-2006 06:35 PM


Originally Posted by quigleybmd (Post 18520)
I've also had the roof & flashing (embedded in the mortar) just redone,

If the water was not getting in near the chimney before the roof was replaced then my opinion is that the roof near the chimney was not installed properly.

The top section of the chimney looks in good condition.

If the water was leaking near the flues then it would be impossible for the water to flow upwards and then to the side of the chimney as shown by your pictures taken in the attic. The pictures from the attic show the water coming from the upper area of the chimney (roof) and then flow downward. The recent roof replacement near the chimney should be investigated for lacking proper flashing.

I would have the roofer remove the shingles at the cricket and inspect for a proper water barrier that extends well beyond the chimney sides and also all the way to the peak of the roof.

If you look at picture #7, it shows the flashing at the base of the chimney and it only extends about 2 inches under the shingles. It would appear that it should extend at least 6 inches or more to the sides of the chimney as this chimney has a cricket.


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