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mstanleyg 10-05-2009 10:07 AM

75 year chimney leak problem
I have a 75 year old cape cod home located on the south shore of long island, ny, with a brick chimney & slate roof. We have a second floor bedroom that has always leaked where the chimney is attached. The leaks appear by the ceiling at the roofline and spread as time progesses. Besides the continuous leaks, the chimney is badly spalling (large pieces of brick facing chipping off) above the roof line only - the rest of the brick on the front of the house require little maintenance.

We have attached the problem from two fronts: the roof was re-flashed and tarred several times to a point where the roofers point to the brick chimney as the problem; the chimney was painted, waterproofed, and sealed several times (it has always been painted) - yet the problem persists with the brick deterioration and leaks. We have gas heat (converted from oil 15 years ago), gas hot water, and have converted our fireplace from wood-burning to gas logs. Some contractors have suggested replacing our clay chimney liners as well with steel - something we haven't done. Based on what I've read, rebuilding the chimney above the roof line appears to be one of the better options available.

Given this, I would appreciate advice on how to approach fixing this problem and the types of contractors I should call.

thank you for any help in this frustrating and damaging problem

stuart45 10-05-2009 10:23 AM

Can you put a photo on? Thanks.

mstanleyg 10-05-2009 02:36 PM

here's the pix
1 Attachment(s)
thanks for the quick response

stuart45 10-05-2009 03:23 PM

Unfortunately painting brickwork often causes more damage to it than protecting it. Once it starts to crack and peel water running down the face enters the cracks but becomes trapped and soaks inside. When it freezes the bricks often spall. Paints have trouble in adherring to most types of brick and stone. Read this.
The oversailing courses are not offering much in weather protection to the stack either. Nowadys we always put in a lead tray that goes through the stack and round the liner to help prevent dampness below.
It is quite a big stack to rebuild.

Ron6519 10-05-2009 04:00 PM

It sounds like you have tradesman who do not know what they're doing working on this. Tarring over flashing is a vain and useless endeavor done by inexperienced people. If the flashing is suspect, have someone evaluate it and have it done correctly if it's the issue.
You don't mention the chimney cap. What shape is it in? At 75 years old, it should have been replaced by now or at least extensively renovated.

mstanleyg 10-06-2009 08:39 AM

Thank you both for your replies!!

Stuart45: Unfortunately, the brick has always been painted. If the stack needs to be rebuilt, any recommendations on how I should treat it (paint it like the rest of the brick, cover it, leave it alone)? Also you pointed out the size of the stack - do you think rebuilding it is necessary - or are other options available? Thanks for the lead tray information - something I will discuss with the contractors I see.

Ron6519: The cap was rebuilt about 25 years ago and seems to be in good shape. The tarring was done over the years after the flashing was redone about the same time - the tar buildup grew with the continuing problem with the leaks.

I have some contractors coming later this week. Are there any obvious directions I should follow? Also, in the past, someone recommended a steel line installation - how can one determine if one is needed?

thank you again for your advice and help

Ron6519 10-06-2009 10:23 AM

"Also, in the past, someone recommended a steel line installation - how can one determine if one is needed?"
The chimney has a fired clay liner. It will deteriorate first at the very top of the chimney. You can go up and inspect the liner on a ladder for the best way to see it, or you can pull the flue pipe out of the wall in the basement to check for a pile of clay pieces on the bottom.
Since you have a fireplace, you should inspect both flues while your at it. Both of the clay flues are made up of segments of pipe cemented together. You want to make sure these connections are sealed together, especially in the fireplace. Embers can escape a deteriorated liner and possibly come into contact with wood framing members. To do a through inspection, you would need to put a camera down the entire length of the flues to make sure they are sound.
If the flues have deteriorated, then you could put a stainless steel liner into the chimnet to provide a continuous path to the roof.
This will not address the moisture/roof leak problem.

MI-Roger 10-06-2009 11:09 AM

Counter flashing and flue liner.........
Make sure the flashing on the chimney includes counter flashing too. The counter flashing is an inverted L-shape (actually more complicated than this but I'll keep it simple) where the short leg of the L in inserted into the mortar joints of the chimney. The long leg then extends downward covering the angle flashing that is woven into the shingles when the roofing is installed.

Too many modern day roofers/masons do not install counter flashings. Instead, they rely on mastics and caulks to seal the angle flashing against the brickwork until the warranty period has long expired. The old way is still the best way! Perhaps augmented with, but not replaced by, modern sealant technologies.

Yes, a chimney liner will be of benefit to you. The flues in your chimney were designed for a much hotter and larger volume exhaust stream than what you currently have with your Natural Gas conversion. The cooler and reduced exhaust gasses are excessively cooled while flowing thrugh the chimney, resulting in them condensing into an acidic liquid. This acid eats thru the clay liners, then eats thru the bricks, and can saturate the bricks from the inside. A stainless steel liner is relatively inexpensive, much cheaper than restoring an old chimney!

A 25 year old chimney cap has probably seem better years too.

stuart45 10-06-2009 01:10 PM

A common problem that we get with old chimneys in the UK is condensation where the chimney breast meets the ceiling due to hygroscopic salts on the surface of the plaster. This is caused by the burning of fossil fuels giving off these salts which are deposited on the walls of the flue. Water vapour is also created as the fuels give off hydrogen and this condenses at the cooler top of the flue. As the flues before 1965 were usually brick and parged the salts were washed through the walls of the flue and into the plaster. These salts attract condensation at an R/H as low as 50% and can cause really damp patches on the plaster.
These wet spots often confuse the roofers who come back time and time again to replace the flashings, re-point the stack, paint silicone over the bricks etc and none of it works as its condensation. In the end they change their mobile phone number to get rid of the punter.
MI Roger has a good point about the counter flashings(we call them soakers) although I didn't know that roofers were not using them anymore.
As regards whether or not the stack needs rebuilding I couldn't really say for sure without a site visit, but if it is rebuilt and painted make sure a micro porous masonry paint is used as this is said to allow moisture to escape.

Gary in WA 10-06-2009 02:02 PM

1. Call an HVAC company to install metal flues inside the old flues as everything is now gas. 2. Call a brick mason to install counter-flashing in the mortar joints above the top of the roof/tar flashing. Paint as mentioned to allow the moisture to escape from the flue leak inside (though the paint may stop peeling once the new flues and a new cap are installed).
Be safe, Gary

mstanleyg 03-30-2010 12:38 PM

Not making much headway
Thank you all for your excellent and timely advice, Since my last post I have an a stainless steel liner installed - apparently it was needed due to the amount of debris found on the inside of chimney base. Also the debate continues with the roofers and chimney people.

At the moment I have a fair amount of water dripping into the front room behind the chimney. It is coming in many above my quarter round windows and on the wall directly behind the chimney. The fellow who installed the liner noticed that the chimney outside appears to be larger than the chimney going through the front room - that is, perhaps for cosmetic purposes the outside masonry was constructed larger than the functioning part. Based on this observation, it appears the water is entering the room from the area or space between the outside and inside portions of the chimney - a space that is about 18" on each side.

While the roof, flashing, and chimney have no obvious openings, this kind of makes some sense to a rookie like me. The damage over the years has been primarily in the three areas I described in the room before. On the outside, if you look at the picture I started with, the inside sides of the quarter round windows could be used as pointers as to where the water is heavily finding its way in. The remaining wall damage seems to be the continued flow of water down the walls.

I am at the point where I would like to replace the old slate roof, flashing, and possibly rebuild the top part of the chimney. I would greatly appreciate any thoughts or guidance of the wisdom of this.


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