# Chimney might have small cracks and is leaking into the house



## proofer (Jan 20, 2008)

I'm guessing, without going up on the roof while it's still raining, that my chimney has small cracks in the concrete. Water is running down both sides of the chimney concrete in the family room. What would you recommend? Do I need a concrete patch and maybe a sealant for spraying the chimney to keep this type of moisture out? I hear that Drylok Fast Plug hydraulic cement is good. Any ideas?


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## Jackofall1 (Dec 5, 2010)

If water is running into the house I would first suspect that the flashing needs attention.

Mark


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## proofer (Jan 20, 2008)

Let me give you a little more information. We had a new roof installed 3 years ago. Also, new flashing as well. It leaked at the same spot at that time after the roof was installed. The roofer came out with his mason and they patched the chimney and sprayed something on it, and it had stopped the leaking for 3 years. Until today. That's why I'm guessing that it's another crack in the chimney because it's leaking through the same way.


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## Jackofall1 (Dec 5, 2010)

Well it sounds like it needs attention whether its the flashing of the brick work, perhaps you could give same roofer a call, I would guess that you don't want to climb up there in the foul weather.

Mark


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## proofer (Jan 20, 2008)

I was thinking of doing something on my own. I think the sealant is something that might work, once I check for cracks. But I will need to wait until things dry up. Any idea on a good sealant?


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## Jackofall1 (Dec 5, 2010)

Yes let it dry, check thoroughly for cracks, spalling of brick, cap or crown on chimney and then apply water proofing.

Heres some that may interest you

http://www.fireplaceandchimneysupply.com/chimneysaver-brick-water-repellents-s/28.htm


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## proofer (Jan 20, 2008)

Got up on the roof today to inspect and take some pictures. What would you recommend I need to do?


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## mem (Dec 15, 2010)

Looks to me that the source of your problem is the chimney cap. The cracking along the top lets water in and will only get worse over time. This is caused by not having an expansion space around the flue(s). As the flue heats up it expands and pushes out on the concrete, causing the cracks. Also, the cap has no drip ledge. All of the runoff from the cap runs down onto the brick, soaks into the mortar and breaks it apart during the freeze/thaw cycles. 

After removing all the loose and cracked mortar between the bricks and repointing it you should remove that cap and construct a new one. There is tons of info on the web as to how to do this properly, including expansion gap, drip ledge, bond break, etc.


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## proofer (Jan 20, 2008)

Thanks, mem, for your advice. I'll show your comments to my husband when he gets home. But in the meantime, I know that the fireplace hasn't been used in years.


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## proofer (Jan 20, 2008)

Well, a couple of days ago I put this tarp over the top of the chimney (see picture below) because we were expecting another downpour. I thought that would keep any water from running down the fireplace on the inside of the house. Well, we still had some water running down the fireplace. So since the cracks (shown in those other pictures) were covered with the tarp, the problem must be in the flashing. I know that I only had a 1-year warranty on the flashing. Any ideas on what good products to use now?


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## mem (Dec 15, 2010)

How about some photos of the flashing details and overall chimney to roof intersection. You may need a pro to re-flash properly if it is failing.

The products jackofall1 suggests may very well work in a pinch, I've never used them, but they will certainly be only a temporary fix. The level of deterioration in your pics indicates a more robust remedy is in order. Casting a new crown is not _that_ difficult, after all, even I manage to do mine! You can check my posts where I've documented the process I used on another thread. I also have a nice article on the subject I can send you--it's too big to post--just PM me.


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## Jackofall1 (Dec 5, 2010)

I have to agree with mem, once seeing the pics, you really should rebuild the top courses of brick, and the crown, this would be in addition to the flashing work.

Mark


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## proofer (Jan 20, 2008)

Three years ago, when the new roof was put on, I believe the mason who did the tuck pointing at that point removed all the mortar around those chimney bricks and replaced all the mortar.


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## tcleve4911 (Nov 6, 2010)

silicone the piss out of 'er !!!!


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## [email protected] (Nov 17, 2008)

First, if that work is only three years old and already falling apart, get a new mason. That mortar had too much water.

Sealants do more damage that good.

I don't see pics of the chimney flashing, but you can get an idea how it should look here; http://www.chimneyflashing.info/


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