# Chimney leaking



## jomama45 (Nov 13, 2008)

That's certainly ALOT of water to be leaking in. My first guess, w/o seeing alot more pictures, would be that the flashing into the chimney is leaking. Hard to guess from that one picture though.

As far as the porosity of the brick, I would find that somewhat unlikely. A porous brick can soak up a vast amount of water before it would actually leak into the inside like your picture. As for the test, an hour should be more than enough to determine how soft the brick are. Fairly soft brick will clearly "bubble" when submersed into water.


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## Just Bill (Dec 21, 2008)

Is there even a cap between the flue and brick???? That is a lot of water.


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## stadry (Jun 20, 2009)

*silicone siloxane for the brickwork. dig down outside & fine where t6he water's coming in ( use your hose ),,, roofing cement over the hole(s) :thumbup:*


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## AgentW (Dec 1, 2010)

> Is there even a cap between the flue and brick???? That is a lot of water.


Mentioned in the post. Yes, there is a good chimney cap and, when opening the damper and examining up the flue, the flues were almost bone dry. Not a chimney capping issue.



> My first guess, w/o seeing alot more pictures, would be that the flashing into the chimney is leaking.


Mentioned in the post. I inspected all of the flashing and it was done correct and is not the culprit. The location of the water (outside of the chimney, almost two feet away from the house), also rules out the flashing.



> As far as the porosity of the brick, I would find that somewhat unlikely. A porous brick can soak up a vast amount of water before it would actually leak into the inside like your picture. As for the test, an hour should be more than enough to determine how soft the brick are. Fairly soft brick will clearly "bubble" when submersed into water.


That's what I thought. Although, we have approximately 342 sq. ft. of brick exposed to the elements and, in this particular storm, that side of the house was experiencing ridiculous amounts of horizontal rain, banging against the chimney.

When I put the brick in water, I did indeed notice air bubbles percolating to the surface, which is definitely something that tells me this may be a very porous brick.


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## stuart45 (Jun 20, 2009)

High porosity bricks often perform better than low porosity bricks, known as the overcoat/raincoat effect. Most of the water comes in through the mortar joints and low porosity bricks send more water into the joints, whereas high soak it up and then it evaporates before reaching the inside.
All the chimneys like yours that I've built were cavity walls ( brick/2-4inch air gap/brick) so water could not reach the inner wall.
There could be a design fault with the stack.


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## jomama45 (Nov 13, 2008)

My mindset is certainly along the same lines as stu's.


We need alot more info on how and wear this thing is built, and more pics certainly wouldn't hurt either. From what I can see from the one pic, this is anything but a typically constructed chimney chase.


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## AgentW (Dec 1, 2010)

Thanks, guys.

I'll see if I can get more pictures. Unfortunately, I don't have any more o the leaks, but can only describe where it's coming in. I do have these pictures available for what the chimney looks like. I can get more specific pictures to add as well. Here is an exterior picture:










Here is the interior firebox (ignore the window leak, I'm already dealing with that BS):


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## AgentW (Dec 1, 2010)

stuart45 said:


> High porosity bricks often perform better than low porosity bricks, known as the overcoat/raincoat effect. Most of the water comes in through the mortar joints and low porosity bricks send more water into the joints, whereas high soak it up and then it evaporates before reaching the inside.


That makes sense. My question though is, what about the freak rainstorm where massive amounts of rain and, specifically horizontal driving rain, saturate the brick. Is it possible to saturate the brick to a point where it cannot hold water any longer and then leaks into the inside of the brick? I mean, a normal rainstorm I can see the brick just soaking it up and then letting it evaporate after it ends. But what about extremely heavy rains? Same thing?


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## jomama45 (Nov 13, 2008)

I would imagine that the entire chase is concrete block backing with brick veneer? Why they used brick for the first 4' is beyond me, but this really should be flashed & weeped to the exterior. Have you tried to get in touch with the mason so he can have a look?

BTW, it's a common mis-conception that masonry veneers are waterproof on their own, they are not. The back-up wall, whether it be wood or masonry, should be water proof BEFORE the veneer goes on and there should certainly be some sort f drainage plane in place (in the wall cavity) that allows any water to exit to the exterior.


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## stuart45 (Jun 20, 2009)

AgentW said:


> That makes sense. My question though is, what about the freak rainstorm where massive amounts of rain and, specifically horizontal driving rain, saturate the brick. Is it possible to saturate the brick to a point where it cannot hold water any longer and then leaks into the inside of the brick? I mean, a normal rainstorm I can see the brick just soaking it up and then letting it evaporate after it ends. But what about extremely heavy rains? Same thing?


Yes, it's possible in heavy, driving rain to penetrate the brick veneer. Thats why we have a 2,3 or 4 inch air gap cavity and then the inside masonry wall. 
This is a drainage system as jomama mentioned. Any new construction should be waterproof whatever the weather throws at it.


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## AgentW (Dec 1, 2010)

jomama45 said:


> I would imagine that the entire chase is concrete block backing with brick veneer?


Nope, this is not a brick veneer. What you see in that first picture (just brick) is how it's built all the way up (other than the firebox/smoke chamber areas, obviously).

I was concerned, when this was being built, that they were just building with brick and not veneering over a cement blocking. However, I was assured by both my GC and mason that this is how chimney's are built.*

*NOTE, now that I think about this, there may have been some brick veneering as well, because he did mention using cement block backing in the chimney. I'm not 100% sure. I apologize if I'm confusing anyone.


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## stuart45 (Jun 20, 2009)

I am not surprised it's leaking if it's only 4 inches thick.


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## jomama45 (Nov 13, 2008)

stuart45 said:


> I am not surprised it's leaking if it's only 4 inches thick.


Nor am I, but I think I'm confused yet to the actual construction.

I was assuming the first picture posted was from the inside of the basement??

If so, that's at least a 8" wide wall, and the brick are flush with the interior & exterior, according to the following picture..........


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## AgentW (Dec 1, 2010)

jomama45 said:


> Nor am I, but I think I'm confused yet to the actual construction.
> 
> I was assuming the first picture posted was from the inside of the basement??
> 
> If so, that's at least a 8" wide wall, and the brick are flush with the interior & exterior, according to the following picture..........


The first picture was indeed taken in the basement.

You make a excellent observation and now, my memory is failing me. I will have to get more detailed pictures. Though the picture looks exactly as you describe, I'm pretty sure there's a lip both on the outside and inside of the foundation wall where the chimney brick rests. I know he did not use cement block there, and I'm pretty positive he did not double up the brick either. There is a huge amount of excess mortar sitting on that ledge of the interior, so it's possible (probable) that is what is making the brick look flush with the interior of the wall.

The foundation, in that particular area, is indeed 8" wide (rest of house is 10"). 

I'm at work now, so I cannot get any more pictures today. Hopefully within the next day I can get more detailed pictures.


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## AgentW (Dec 1, 2010)

stuart45 said:


> All the chimneys like yours that I've built were cavity walls ( brick/2-4inch air gap/brick) so water could not reach the inner wall.
> There could be a design fault with the stack.


I was reading through this again and must have missed this part the first time around. Since I'm not overly familiar with this portion of construction, could you help me out here?

Is what you mention above the standard way to build a chimney? In other words, 2x4inch brick, air space, and then 2x4 inch brick inside that brick? 

I know that's not how this was constructed in most areas. it's just the 2x4 inch brick, plus the necessary work for the flue, firebox, smoke chamber, etc... In other words, I'm near 100% positive that, above the smoke chamber, it's just 2"x4" brick all the way up (at least to the rake, where they may have made some adjustments there).

I do have a question on the above though. If you have a 8" foundation base, and you lay 2"x4" brick and then air space (what's standard air gap?), and another 2"x4" brick, you're going to exceed the 8" foundation base. Do you use an angle iron to get around this? Do you lay the inner brick on it's shorter side to only take up 2"?



jomama45 said:


> From what I can see from the one pic, this is anything but a typically constructed chimney chase.


As I mentioned above, I'm not overly familiar with proper chimney/fireplace construction. Would you be able to elaborate as to why this doesn't appear to be a typically constructed chimney chase?* And, would you be able to explain what a typical constructed chimney chase would consist of? Any information would be greatly appreciated.

* What is a "chase"? Is that simply the brick exterior of the chimney going up?


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## stuart45 (Jun 20, 2009)

I might have confused the issue here. That is the standard method in the UK where damp penetration is a major problem with buildings. The foundations are usually at least 2 ft wide in a trench and the cavity walls are brought up from below ground level.















Jomama will know better than me on the correct method of chimney construction over your side of the Pond. I am interested to see the differences in construction.


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## jomama45 (Nov 13, 2008)

Long day & it's too late now, but i promise that I'll post an in-depth description & explanation in the next few days......................... :thumbsup:

And the more I look at the pics, the more I find myself asking WTF?????


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## Michael Thomas (Jan 27, 2008)

That's a WHOLE lotta' water!

1) Water (especially wind-driven rain) can pass through brick veneer and penetrate to the interior if the walls detailing is incorrect:










but in my experience it's not likely THAT much water is coming though the masonry itself, though if you want to be certain the wall is not highly absorbent you can get someone to perform a RILEM test. 

2) It's tough to properly flash that uphill junction at that chimney projection at the rake (we just has a long discussion of this issue here recently, but I can't find the thread at then moment) - and it's certainly one suspect. My preference for that flashing is a "half cricket" which deflects ALL water around the chimney to the side opposite the rake, though most posters here feel that's overkill. If you are spilling water over the rake edge, it obviously has the potential to enter anywhere along the length of the chimney below at its intersection with the cladding.

3) Without seeing the top of the chimney, there is no way to know if the detailing there is correct, and this is a potential source of significant water entry.


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## AgentW (Dec 1, 2010)

jomama... thank you. I look forward to your post. I have a meeting with my G.C. tomorrow morning, so I'd like to be as informed as possible before that talk.



Michael Thomas said:


> 1) Water (especially wind-driven rain) can pass through brick veneer and penetrate to the interior if the walls detailing is incorrect:


I've heard this as well. Just so we're on the same page, this is not a brick veneer, but a solid brick chimney. I went and talked to the gentleman we bought the brick from and he truly does not believe this would be water coming through the brick. It's a high end Belden brick, which he believes should not experience this type of problem.

The rain that came through WAS heavy, and I mean really heavy, wind driven sideways rain. The side of the house with the chimney was the side that was experiencing the brunt of this rain. While it was raining all day, the sideways rain was occurring for about an an hour and a half to two hours before I noticed the water (though, I readily admit that it could have started earlier in the day, as I was working in an entirely different portion of the house most of the day).

Also, during the construction of the chimney, when the top was still fully open, we never saw water like this. Though, we never had a storm quite as bad as the one this past weekend.



Michael Thomas said:


> It's tough to properly flash that uphill junction at that chimney projection at the rake (we just has a long discussion of this issue here recently, but I can't find the thread at then moment) - and it's certainly one suspect. My preference for that flashing is a "half cricket" which deflects ALL water around the chimney to the side opposite the rake, though most posters here feel that's overkill. If you are spilling water over the rake edge, it obviously has the potential to enter anywhere along the length of the chimney below at its intersection with the cladding.


Agreed. I had discussions about this exact particular area prior to the having this issue. However, we opted away from the half-cricket, since the majority of the fireplace is outside the rake. 

The main issue, though, is that even if there was an issue with the flashing, or even the caulking along the intersection of the chimney with the sheathing, it would not have manifested itself in this type of leak.

Let me explain what I mean by this. From a construction stand point, the brick comes out two feet from the sheathing, across 5 feet, and then back in two feet towards the sheathing. The areas of the brick that were wet (soaked) were the entire exterior 5 feet, and maybe a foot in on each side. The brick along the sheathing was completely bone dry. If there was an issue with the flashing on the roof over the rake, or along the sheathing, I'm fairly certain that the brick along the sheathing would have been soaked as well.



Michael Thomas said:


> 3) Without seeing the top of the chimney, there is no way to know if the detailing there is correct, and this is a potential source of significant water entry.


I'm going to attempt to get up there this weekend to take pictures. It's just difficult right now, as I no longer have the mechanical lift on site, and with the temps in the low teens right now, it's tough to get on the roof as the shingles are often iced over. 

I can explain that the top of the chimney has two rows of bricks that come out slightly further than all the rows below them, creating a small step out. The chimney has a cement/mortar cap up to the two flues, and there is a stainless steel cap covering the two flues. The stainless steel cap does not cover the entirety of the cement/mortar cap. I confirmed that the screws that were used to install the stainless steel flue cap were caulked and sealed.

The only thing I can see is that the cement/mortar cap is not angled the way I think it should be done. There 'is' an angle, but it's not as steep as I think it should be to create the proper run off. However, since the flue's were completely bone dry, I really don't necessarily see that as the problem.

One thing I know is that the mortar joints are significantly more porous than the brick itself. So, if this is an issue with the mortar joints and not the brick, is there a likelihood it's due to an improper type of mortar?

I mean, I keep hearing about sealing the chimney, which I'm obviously going to have to do. However, I know tons of large buildings in my area that are all brick and mortar, and I know they did not seal them. I cannot believe that they're experiencing this type of water intrusion from driving rain.

Again.. thank you guys for your help and information. This is an area of construction where I'm fairly weak and even google searches don't necessarily provide quite the information I'm looking for.


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## Michael Thomas (Jan 27, 2008)

Re: chimney caps, take a look here:










- Chimney Caps To Last A Lifetime

WRT the exit of the water at the junction of the chimney with the foundation, is there visible evidence of a through wall flashing at this location? Water sometimes either travels along such flashings to exit at a point some distance horizontally for the vertical position of leak, or spreads out from a narrow stream of water at the interior and out along the flashing.

Do you have any pictures of the chimney during construction, or a clear recollection of a cross section view of the chimney above the foundation? How to the construction drawings indicate the chimney should have been built?


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## Michael Thomas (Jan 27, 2008)

BTW, I'd very much appreciate it if you would keep us informed on your progress and the eventual diagnosis and solution, one of the most frustrating experiences here it to follow the progress on one of these investigations for a few days or weeks, and then never learn the actual problem and the successful fix so we can help the next person with a similar problem.


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## AgentW (Dec 1, 2010)

Michael Thomas said:


> Re: chimney caps, take a look here:


I can say that the chimney cap we have is not quite like that. Basically, at the top of the chimney, they created the 2 inch spacing from the main chimney with brick. So the top two rows of brick go out 2" further than the main stack. Then, the cement/mortar cap goes directly over those top of the top row of those two rows of brick. The cement cap does not overhang the brick.

NOTE: In the pdf link you provided, it's created like the second picture (1976-1985).



Michael Thomas said:


> WRT the exit of the water at the junction of the chimney with the foundation, is there visible evidence of a through wall flashing at this location? Water sometimes either travels along such flashings to exit at a point some distance horizontally for the vertical position of leak, or spreads out from a narrow stream of water at the interior and out along the flashing.


I don't remember any kind of flashing where the brick meets the foundation. I believe he just bonded the brick directly to the foundation. You can see this juncture point in the first picture (with all the water). I know there is nothing visible in the interior or exterior.



Michael Thomas said:


> Do you have any pictures of the chimney during construction, or a clear recollection of a cross section view of the chimney above the foundation? How to the construction drawings indicate the chimney should have been built?


Unfortunately, I have no pictures like this. I have some idea of how it was built, so I can potentially answer any questions you may have.



Michael Thomas said:


> BTW, I'd very much appreciate it if you would keep us informed on your progress and the eventual diagnosis and solution, one of the most frustrating experiences here it to follow the progress on one of these investigations for a few days or weeks, and then never learn the actual problem and the successful fix so we can help the next person with a similar problem.


I will definitely try to do that. The only current 'solution' I have right now is to seal the brick and mortar. Unfortunately, that cannot be done until March or April, as it's currently in the low 20's to teen's and, from what I have read, most sealers require a minimum of 40 degree temperatures.


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## jomama45 (Nov 13, 2008)

There's any number of things that I notice just from those three pictures that I would consider non-typical construction. Some may just be due to the fact that different markets use different approaches, but there certainly a few issues, at the very minimum, that are less than ideal for successful masonry construction. Regardless, something(s) obviously wrong if the chimneys leaking this bad. Even with the amount of rain you're explaining, there's no reason this should be leaking inward. Here's a few observations: (although some may be a stretch because I can't see every detail in the pics)

- At the base of the wall, there doesn't appear to be any dropped brickledge. In my experience, w/o the brickledge, 9 times out of 10 any water inside the cavity will have the tenancy to leak inward. If I were to have constructed the chimney, I would have request a 4" deep by 8" high pocket formed into the top of the foundation wall at the base. Better yet, I would have requested a 10" wide wall through the chimney like the rest of the house, and the wall would have gone the full 9' high. The below grade would have been 10" wide, and everything above grade would have been 6" wide, leaving a 4" brick ledge. It's just the most efficient way to construct it.

- I see no evidence of weeps or flashing at the base.

- While the interior firebox looks alright, I can spot a few questionable things. Where's the wall ties, as it's obvious by looking at the firebrick floor that the FP surround will be full veneer. Is there at least 1" clearance to combustables at the sides & top??? Doesn't quite look like it. And why is the wall sheeted behind the FP? Maybe it's just the way we do it here, but it would have been easier on the mason, and likely made a better job all together, if the studs where left out between the massive shoulders until the chimney was done. (maybe they were now that I think of it?)

- I can't tell from the pic, but the cap certainly should overhang ALL brick by at least 2", and look exactly like Michael's link. Corbelling the top two courses isn't enough to keep water dripping past the brick.

- How a mason can properly detail and construct a chimney of that size without using concrete block (CMU) is beyond me. Obviously, one can't. The inner wall (back wall) should be made of a material that's far more rigid & strong than the veneer that's attaching to it. It should also be waterproof, which isn't easy to do with brick. Not to mention, why in the world would someone lay all those extra brick when block are stronger, faster, offer better water resistance, can be easily re-enforced if necessary, far cheaper, etc.... It makes no sense to me that the entire chimney was built with two wythe construction.

- I think that the roof/chimney connection could certainly be the source as well. In that kind of height, water can move horizontally pretty far before far before it exits. I would run a hose right above that flashing for a period of time (when the weather allows of course) to see if you can replicate the leaking again.

- DO NOT seal the brick until you are 100% sure you have found the leak. I probably wouldn't seal the brick at all if it can be helped. Seeing you already have an avenue to talk to the Belden, I would certainly recommend calling them to first as well to verify that their brick can be sealed. Picking up spalled brick faces in spring just so you can mow the lawn is not a situation you want to be in.

Here's a link as to how conventional masonry/cavity walls are meant to be constructed. Page 5 has the most pertinent illustrations. Note that they show a double wythe wall detail with integrated flashing as well in the link.

http://www.gobrick.com/html/frmset_thnt.htm
(on edit, go to article 7, Dec 2005)

Good luck, and certainly let us know what's discovered after meeting w/ the builder. :thumbsup:


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## stuart45 (Jun 20, 2009)

Great info and an interesting link Joe. Sealer is a last resort to poor construction. 
Here's an example of a more modern method of constructing a chimney here. They used to be solid brickwork, but now the jambs are usually voids.


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## Michael Thomas (Jan 27, 2008)

Yup... IMO we really need:

1) To know more about the chimney's construction.

2) A good look at the top of the chimney

before we can get much further.

BTW, I an NOT suggesting the OP get up on that roof in the winter, or at any other time, unless they are certain it is safe for them to do so. 

Given that there is this much water penetration, if this chimney is serving only the fireplace, I would suggest that one obvious diagnostic is to have someone get up there and (assuming they do not observe some obvious mode of water entry at the cap) *after having made certain (via signage at the chimney or some other method) that no one will attempt to use the fireplace* tarp off top 2-3 feet of the chimney and see if the water intrusion stops, .


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## jomama45 (Nov 13, 2008)

stuart45 said:


> Great info and an interesting link Joe. Sealer is a last resort to poor construction.
> Here's an example of a more modern method of constructing a chimney here. They used to be solid brickwork, but now the jambs are usually voids.
> View attachment 27810


Actually fairly similar Stu. :drink:


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## hereslookingatU (Feb 8, 2010)

Hi!

An interesting problem that you have, one that has caught my attention! 

First comment, just to set the record straight - 'yes' the brickwork will let penetrating rainwater in, and in torrents in the conditions that you have described. The reason you don't see the damp when looking up the flue is that the damp is between the brickwork and the external face of the flue.

One thing you seem to be short on is lead dpc's/trays and weep holes especially with such a large exposed flank.

I have hopefully managed to attach a file issued by zurich insurance which provides a best practice method for constructing chimneys and you may wish to measure your construction detail against this standard.

I hope this information is of some assistance.
Regards


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## Michael Thomas (Jan 27, 2008)

I've always thought that the English practice of through-wall flashings at chimneys is a good idea, but you never see it (at least I've never seen it) done in the US.


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## hereslookingatU (Feb 8, 2010)

Hi Michael

To be honest you do not see this level of detail on modern chimney stacks as the design generally speaking follows the principles of the diagram provided by Stuart45 on discussion thread 25. Having the cavity wall construction does away with the need for the intermediate flashings, but you would still retain the 3 trays shown in the 'zurich detailed design' above roof level. 

Below the roof line the rainwater would enter the cavity and flow down the inside face of the external brickwork where it would either evaporate or travel down to below dpc level where the cavity will be filled with sharp sand and cement and camfered to a fall to the outside of the building below dpc level and weep holes would allow the water to escape where it can do no harm.

The only problem comes where the cavity has not been kept clear of debri and mortar snots and in some situations insulation material which then allows the rainwater to breach the cavity and cause damp problems inside the building (which is not that uncommon in the UK).

The full extent of AgentWs problems is shown in the first photograph shown on AgentW discussion thread. The photograph shows the trapped rainwater perculating out at base level of the chimney stack between the render and the face brickwork, which is solely caused by the volume and head height of rainwater trapped behind the face brickwork and the internal flue. 
Water will always seek the path of least resistance and the flue being of a denser material than the brickwork means that the rainwater will eventually force itself out through the brickwork, the render at low level then provides a barrier and the rainwater perculates out as shown in the photograph. 

This does not mean that rainwater will not penetrate further up the chimney stack as it meanders its way to the base of the chimney stack as is evidenced by the damp problems at first floor, as already mentioned water will always seek the path of least resistance.

Regards


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## AgentW (Dec 1, 2010)

First... thank you for a long, detailed, and thorough post. Greatly appreciated. 



jomama45 said:


> - At the base of the wall, there doesn't appear to be any dropped brickledge. In my experience, w/o the brickledge, 9 times out of 10 any water inside the cavity will have the tenancy to leak inward. If I were to have constructed the chimney, I would have request a 4" deep by 8" high pocket formed into the top of the foundation wall at the base. Better yet, I would have requested a 10" wide wall through the chimney like the rest of the house, and the wall would have gone the full 9' high. The below grade would have been 10" wide, and everything above grade would have been 6" wide, leaving a 4" brick ledge. It's just the most efficient way to construct it.


I never quite thought of that. I'm not sure if the mason would have preferred that design or not. Unfortunately, one of the drawbacks of this project that I've noticed thus far is a lack of communication between subs. It just seems there's an attitude of "I do it my way and the other subs that come in will have to work with it that way."



> - I see no evidence of weeps or flashing at the base.


That's because there are none. 



> - While the interior firebox looks alright, I can spot a few questionable things. Where's the wall ties, as it's obvious by looking at the firebrick floor that the FP surround will be full veneer. Is there at least 1" clearance to combustables at the sides & top??? Doesn't quite look like it. And why is the wall sheeted behind the FP? Maybe it's just the way we do it here, but it would have been easier on the mason, and likely made a better job all together, if the studs where left out between the massive shoulders until the chimney was done. (maybe they were now that I think of it?)


There are definitely wall ties, but you cannot see them in the pictures I've posted. Also, the build out of the fireplace (cement block) goes further in front of the firebox than it looks. We should have all of the necessary clearance in that area.

The wall was sheeted behind the fireplace because of a lack of communication and probably some poor sub-management, in terms of timing, on the part of the G.C. It definitely would have been easier if the fireplace/chimney was built before the builders finished, but that's just not how it was done. In fact, the mason wanted to have the header moved up higher to make it easier, but was forced to work with it at the height you see in the picture.



> - I can't tell from the pic, but the cap certainly should overhang ALL brick by at least 2", and look exactly like Michael's link. Corbelling the top two courses isn't enough to keep water dripping past the brick.


I have better pics of this that I took this weekend (had a warmer day where I could get the 40' ladder out and get on the roof) which I will post later.

I do dislike and question the overall design of the cap. As I mentioned earlier, I don't necessarily think it's 100% wrong, based upon the fact it's how it used to be done. I just know it's not the best way to do things. That's one of the things that I'm finding with most of the contractors I've talked with our dealt with. They do things that aren't necessarily wrong, but they're certainly not the best way to do it.

To describe the construction, the stack comes up, and then he bumps out about 2-3 courses of brick about a half inch (I thought it was 2", but it's not even close to that). On the top of the top row of brick, he starts the cement cap (the cap covers the entirety of the top row of brick, but does not overhang the brick).

Here is where I have some concerns beyond just the old design. He angles the cap up, but then comes to a pretty flat section around the flues. My understanding is that the entire top of the cap should ALL be angled, not just the edges. In essence the top kind of looks like this:
__
/===\

... though not as steep of an angle to the flat section.

There are two flues and, again, I dislike how the wood burning stove flue (smaller of the two) only has about a half inch (give or take) clearance from the cement cap, while the wood fireplace flue has probably at least 6 inches, maybe more.

Finally, and this was done by the G.C. and not the mason, the stainless steel cap is placed over the flue. This was done fine, except for one thing I noticed this weekend. When he put the cap on, he caulked the screw holes appropriately, so I was happy with that. However, for some reason which I can only divine as not understanding 'why' things are done (EDIT: I've since found out that the manufacturers instructions say to do it this way... makes no sense to me), he caulked the entire nailing flange of the stainless steel cap to the cement cap. Basically, he created a situation where all of the water would be sealed inside the cap. Luckily he caulk all of the flange holes, as there are several higher screw holes that do not have caulk and that will allow the water to weep out before it gets too high. I'm just baffled as to why you would even think to caulk that, as you want the water to run away, not stay there.



> - How a mason can properly detail and construct a chimney of that size without using concrete block (CMU) is beyond me. Obviously, one can't. The inner wall (back wall) should be made of a material that's far more rigid & strong than the veneer that's attaching to it. It should also be waterproof, which isn't easy to do with brick. Not to mention, why in the world would someone lay all those extra brick when block are stronger, faster, offer better water resistance, can be easily re-enforced if necessary, far cheaper, etc.... It makes no sense to me that the entire chimney was built with two wythe construction.


So, I have a little more info on the construction of the chimney. The entire inside wall of the chimney (along the sheathing of the house) is cement block all the way up to the rake of the house, where he splits to all brick. The exterior three walls of the chimney are solid brick, not a veener on cement block.

Also, I'll note that we're using zip board, not Tyvec, as our vapor barrier.



> - I think that the roof/chimney connection could certainly be the source as well. In that kind of height, water can move horizontally pretty far before far before it exits. I would run a hose right above that flashing for a period of time (when the weather allows of course) to see if you can replicate the leaking again.


I think they could be the source of other problems, but the fact that all of the brick within a foot of the house sheathing was bone dry says that it's just not the flashing. I agree that water can move horizontally before it exists, but it would attempt to move vertically first, as that's the path of least resistance. I cannot see a single scenario where the flashing is leaking THAT much and none of the brick within a foot of the house have a single drop on them, but all of the brick a foot out and beyond are drenched.



> - DO NOT seal the brick until you are 100% sure you have found the leak. I probably wouldn't seal the brick at all if it can be helped. Seeing you already have an avenue to talk to the Belden, I would certainly recommend calling them to first as well to verify that their brick can be sealed. Picking up spalled brick faces in spring just so you can mow the lawn is not a situation you want to be in.


I've had that conversation with the supplier, and he believes there should be no problem sealing the brick. However, he still can't understand why we are in a situation where we 'need' to seal the brick.

I did notice a few things upon further inspection that do concern me. When I stood up inside the basement portion of the chimney, where I have the best access to the interior masonry work, I noticed that a majority of the head joints were NOT completely filled. All of the bed joints were oozing mortar, but many of the head joints maybe had a 2" air space until you reached the mortar, sometimes more, sometimes less.

Since mortar is the section of the brick that's most likely to let water through to the interior, I have to believe the lack of an extra 2" of mortar is a potential culprit for this particular water intrusion (I'd say leak, but there's far too much water to be a 'leak').

Combine that with the fact that the chimney was only finished a week or so prior to the driving rainstorm (mortar not fully set up), and I think that's the most likely cause.

At this point, I'm near 100% certain that a good sealer will work. However, my bigger concern with the head joint issue revolves around the longevity of the chimney, and how that will have an effect. Any ideas?

Finally, one of the things I'm coming across is that there really appears to be very little recourse for myself, as a homeowner, as there are no standards for what is unequivocally right or wrong. What he did may not be the 'best' practice, but from everyone I'm talking to, it's not wrong to the point where I can force him to rectify the situation by tearing it down and doing it right, at his expense (EDIT: I have not confirmed about the head joints yet). So, I'm stuck in a situation where I have to spend money to seal a chimney every 3-5 years just to be safe.


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## SteelToes (Oct 5, 2010)

*Chimney Leak*

Great thread and great posts guys.
I just wanted to share my opinion..
Looking at the first attached picture it looks like water was penetrating in-between top of the foundation concrete wall and bricks, again looking at the picture you can also see that part of the mortar that sits above the foundation wall is dry and part of the mortar is wet. That small section explains your problem; if there was a leak at the roof-chimney flashing section in this early stage of construction you would be able to notice that on the interior side of the sheathing. Overall in my opinion chimney is constructed well, chimney cap could be better agreed. I don't think there is a problem with brick and I can still see some cinder blocks outside by the chimney, so yes they have used cinder blocks...
Your problem is that you have no flashing at the brick-foundation wall section...water runs down the chimney and easily penetrates thru generous amount of mortar that is in between brick and the foundation wall. Why?
Your chimney cap should overhang for at least 2" inches..Period
You need to have flashing where brick meets the foundation wall.
You can fix this problem with a drip edge and a piece of T-bar, have your GC bend a drip edge apron and attach with a piece of T-bar, caulk the T-bar and that should take care of the leak.


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## AgentW (Dec 1, 2010)

SteelToes said:


> Looking at the first attached picture it looks like water was penetrating in-between top of the foundation concrete wall and bricks, again looking at the picture you can also see that part of the mortar that sits above the foundation wall is dry and part of the mortar is wet.


I apologize that I have not posted better pictures. I can tell you that while it's possible there is water penetrating between the foundation wall and the brick, that is not where this issue originates. All of the brick above the foundation wall was soaked (except for the bricks along the sheathing of the house), so the wet mortar you see and the water on the foundation, was what ran down to that junction, not what came through.



> That small section explains your problem; if there was a leak at the roof-chimney flashing section in this early stage of construction you would be able to notice that on the interior side of the sheathing.


Agreed. I would also notice it along any of the cement block or brick that backs the sheathing. That portion of the interior of the chimney was dry. The origination of the water intrusion was most definitely not the flashing. Now, that's not to say that there couldn't be some issue with the flashing I'm not seeing that could potentially become an issue. I'm just 100% positive that whatever issue there could potentially be with the flashing (I believe there is none based upon my inspection) would not have caused this issue.



> Your problem is that you have no flashing at the brick-foundation wall section...


While it would be great to have that, I'm not sure how that flashing at the foundation would have solved the issues of the water coming in from above and seeping down into the firebox.


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## jomama45 (Nov 13, 2008)

AgentW said:


> Also, the build out of the fireplace (cement block) goes further in front of the firebox than it looks. We should have all of the necessary clearance in that area.
> 
> Let me just clarify here. You need 1" min. clearance from any & all block to any combustable/wood. This 1" gap is closed in by the exterior brick veneer. If you can't get your fingers between the interior block and the stud & sheathing, there's definately a problem. The same goes for the exterior of the chase, which you obviously can't see now because it's sheated.
> 
> ...


You really need to get familiar with a current copy of your jurisdictions building codes. I tried to look real quick online, but I only got far enough to find that it appears RI adopted the IRC code. What specific changes, if any, have been adopted by your area I don't know. But, I have a hard tie believing in this day & age that any non-arid state in the US doesn't require wall flashing & weeps at the base of the wall. Our code in WI is very specific with many of these items, and has been for 20+ years.



AgentW said:


> I apologize that I have not posted better pictures. I can tell you that while it's possible there is water penetrating between the foundation wall and the brick, that is not where this issue originates. All of the brick above the foundation wall was soaked (except for the bricks along the sheathing of the house), so the wet mortar you see and the water on the foundation, was what ran down to that junction, not what came through.
> 
> 
> 
> ...


Now that I read this post, I' beginnig to think you indeed only have a single wythe wall on the exterior three walls. If that is acceptable by code, or anyone as acceptable building practice, I certainly feel for you. Brick veneer, especially at those heights, isn't intend to stand alone on it's very own. If it was, we wouldn't be using wall-ties for attachment to the home........................


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## stuart45 (Jun 20, 2009)

jomama45 said:


> Now that I read this post, I' beginnig to think you indeed only have a single wythe wall on the exterior three walls. If that is acceptable by code, or anyone as acceptable building practice, I certainly feel for you. Brick veneer, especially at those heights, isn't intend to stand alone on it's very own. If it was, we wouldn't be using wall-ties for attachment to the home........................


I think the same Joe. When I look at the photos it does look like the wall sits in the centre of the 8 ins concrete.
Also the fact that half filled head joints can be seen further up suggests that this is the back of a 4 inch wall, as a 9 inch wall would usually have the backs filled and maybe the centre empty.


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## AgentW (Dec 1, 2010)

Hey Joe... thanks again.



> So, the three exposed walls of the fireplace are one
> wythe (about 3.5") wide? If that's the case, you certainly need to do
> some digging through your code, as there's no way I can see that as
> being acceptable.


Here is what I found in RI building codes (though, this is from 2006 and could have changed)


2113.10 Wall thickness. Masonry chinmey walls shall be con- 
structed of concrete, solid masonry units or hollow masonry 
units grouted solid with not less than 4 inches (102 mm) nomi- 
nal thickness. 

2113.10.1 Masonry veneer chimneys. Where masonry is 
used as veneer for a framed chimney, through flashing and 
weep holes shall be provided as required by Chapter 14. 


From the sounds of this, the mason was not building against code. He was using solid brick, 4 inches in width, ant not as a veneer. This tells me you only need through flashing and weep holes for a veneer, not a solid brick design.


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## AgentW (Dec 1, 2010)

> Now that I read this post, I' beginnig to think you indeed only have a single wythe wall on the exterior three walls. If that is acceptable by code, or anyone as acceptable building practice, I certainly feel for you. Brick veneer, especially at those heights, isn't intend to stand alone on it's very own. If it was, we wouldn't be using wall-ties for attachment to the home........................


Maybe I'm confused, or not explaining myself accurately, but I thought I made it apparently from the beginning that a solid brick wall was built, not a veneer wall.

Is a brick used for a brick veneer different from a standard solid brick?


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## AgentW (Dec 1, 2010)

stuart45 said:


> I think the same Joe. When I look at the photos it does look like the wall sits in the centre of the 8 ins concrete.
> Also the fact that half filled head joints can be seen further up suggests that this is the back of a 4 inch wall, as a 9 inch wall would usually have the backs filled and maybe the centre empty.


Yes, the brick does sit in the center of the concrete foundation wall. Well, not fully in the center. The exterior pas probably an inch or so of space, while the interior has maybe 3 inches.


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## stuart45 (Jun 20, 2009)

AgentW said:


> Maybe I'm confused, or not explaining myself accurately, but I thought I made it apparently from the beginning that a solid brick wall was built, not a veneer wall.
> 
> Is a brick used for a brick veneer different from a standard solid brick?


Usually the same bricks are used. 
Have a look at the slenderness ratios of brick walls.
http://books.google.co.uk/books?id=...rickwork&source=bl&ots=VlrEImDYPY&sig=8Xtlm_L


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## hereslookingatU (Feb 8, 2010)

Hi AgentW

Any chance that you can post some sketch's with dimensions showing on plan how the chimney stack is constructed, say one at about basement level, one about the throat to the fireplace and one halfway up the stack. If you wanted to finish off, for good measure one of the top of the stack. No need for isometric's!

They say that one picture is worth a thousand words and sometimes this is very apt! Although I am asking for 3-4 sketches, its not likely that you will get three-four thousand words in exchange! But I may exchange your sketches for a few rare pearls of wisdom from what is a very rare commodity! :whistling2:

Regards
GJ


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## Michael Thomas (Jan 27, 2008)

Also, can you upload the new pictures of the chimney cap?


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## hereslookingatU (Feb 8, 2010)

Hi AgentW

On a technical note: a 4" wall is a 1/2 brick solid wall and a 9" (one brick length depth) wall is a 1 brick solid wall. A 1 brick wall is how most solid walls are built in the older houses in the UK and most do not have any problems, some may have a problem due to the type of brick that was used and to get over the problem by applying a 2 coat render to the brickwork. 

However, a house would never be built with only a 4" 1/2 brick wall as it would never withstand the weather conditions that you have described, hence why you are having so much of a problem with rainwater penetration, which is worsened by the fact that you have no lead trays etc by which to channel the rainwater back to the external face of the building. 

The only time you get a 1/2 brick wall in the UK is with the front skin of a cavity wall construction, the cavity acting as a line of defence to the penetrating rainwater, regretfully a cavity is something that you do not appear to have.

Regards
GJ


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## jomama45 (Nov 13, 2008)

AgentW said:


> Hey Joe... thanks again.
> 
> 
> 
> ...



The problem comes in here:

A) He used brick that were designed & manufactured to be used as a veneer product only as the framing/structure of the chimney walls. Give the folks at Belden another call and ask them if this is an intended use for these specific brick.

B) Even though I'm not real familiar with the IRC code, I'm positive that it includes verbage stating that the chimney CAN NOT allow water to leak through. Call your building inspector & voice your concerns. I'm really having a hard time grasping that this sort of masonry construction is acceptable by any code in this country. Even if it were, it certainly wouldn't have the blessing of the brick manufacturer.

Good luck with the situation.


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## DIY_ing_Guy (Nov 19, 2010)

I can't offer a detailed technical explanation, but I had a similar problem so I'll speak up. I have a very similar chimney configuration (I even have almost the same windows on each side.) Our house had a new roof installed just before we bought it. It was changed from wood shake to asphalt/fiberglass shingles, so plywood sheathing was installed for the first time when it was re-roofed. 

After 3-4 years, water started dripping... then pouring... into firebox, and on through basement ceiling underneath. Your pictures could have been my house. I sealed every crack in the cap, checked all the flashing, etc. No progress.

I hired a reputable roof repair guy who also advertised "leaking chimney repair," he found that the sheathing was not properly supported against the chimney... it was allowed to "hang over" the nearest rafter to abut the chimney. This allowed movement which caused failure around the apparently good flashing. He properly supported the sheathing, re-flashed, and re-shingled, and after 3 years we have had no more leaks.

Guy


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