Brick Chimney Damage - Opinions Wanted

vetrano · Feb 21, 2016

The brick on my chimney has started to deteriorate, especially on the south side. I received a few quotes and everyone agrees that the portion above the roof should be rebuilt, but I am getting differing opinions on what to do below the roof.

Some masons are recommending cutting out only the damaged (spalled or cracked) bricks and replacing them while others have recommended that I should tear down the whole chimney and rebuild it as it is only a matter of time before the other bricks incur similar damage.

Obviously rebuilding will cost more than replacing the individual bad bricks, but I don’t want to do a cheaper repair if it means I’m going to have to revisit it in the near future. I have researched here and online and still don’t feel I have a good grasp of how likely the remaining bricks are to deteriorate.

I attached a few photos. I’d like to get opinions from any experts or even people who have gone through this. I’d like to figure out the scope I want and then I’ll get the contractors that I’m most impressed on to requote on the same scope.

GeHmTS · Feb 21, 2016

Just curious, are you aware of any previous damage to the chimney such as a fire? It looks like some repairs have already been done. I'm referring to the white band around the chimney near the top.

bholler · Feb 21, 2016

GeHmTS said:
Just curious, are you aware of any previous damage to the chimney such as a fire? It looks like some repairs have already been done. I'm referring to the white band around the chimney near the top.

That is holding an antenna

bholler · Feb 21, 2016

vetrano said:
The brick on my chimney has started to deteriorate, especially on the south side. I received a few quotes and everyone agrees that the portion above the roof should be rebuilt, but I am getting differing opinions on what to do below the roof.

Some masons are recommending cutting out only the damaged (spalled or cracked) bricks and replacing them while others have recommended that I should tear down the whole chimney and rebuild it as it is only a matter of time before the other bricks incur similar damage.

Obviously rebuilding will cost more than replacing the individual bad bricks, but I don’t want to do a cheaper repair if it means I’m going to have to revisit it in the near future. I have researched here and online and still don’t feel I have a good grasp of how likely the remaining bricks are to deteriorate.

Pretty much those are your options. I know in our area there are some brick that i would recommend a completer rebuild of they looked like that and other brick i would patch. I don't know those brick or your area so i cant advise on the best option. But patching is a gamble I think usually it pays off but the masons in your area will know best

vetrano · Feb 21, 2016

bholler is correct - those bands are holding an antenna. No chimney fire I know and I had a chimney sweep out a month ago and he didn't say anything other than the brick needs attention.

Also I'm planning to put a wood insert in. Given that the chimney needs at least a partial rebuild am I better off having it built with a clay flue liner and install a stainless liner inside of that or is there a better option?

vetrano · Feb 21, 2016

bholler said:
Pretty much those are your options. I know in our area there are some brick that i would recommend a completer rebuild of they looked like that and other brick i would patch. I don't know those brick or your area so i cant advise on the best option. But patching is a gamble I think usually it pays off but the masons in your area will know best

Problem is I'm getting differing opinions for different masons on the below roof portion. As for the brick I have been told it has not been the most reliable by a mason as well as a masonry supply shop.

bholler · Feb 21, 2016

vetrano said:
Problem is I'm getting differing opinions for different masons on the below roof portion. As for the brick I have been told it has not been the most reliable by a mason as well as a masonry supply shop.

In that case i would probably recomend a total rebuild but it is had to say with the limited info and views i have.

vetrano · Feb 21, 2016

If doing a total rebuild with the plans for a wood insert would you build the chimney with clay flue tile (8"x12") and then put a stainless steel liner in it for the insert or are there other options to consider (considering I want the brick chimney to match the house).

bholler · Feb 21, 2016

I wouldn't put clay in at all in that case

jetsam · Feb 22, 2016

I don't know anything about brickwork, hoping bholler can educate me a bit

I see bricks with chips out of the surface, but maybe only 2 bricks below the roof that have cracks as opposed to cosmetic issues, and maybe 1 or 4 above the roof.

Why is anyone saying this should be rebuilt? (I believe you guys when you say there's a problem but I don't see it in the photos.)

What caused that interesting column of chipped bricks on the one side above the roof? Is that caused by the chimney leaning out over that corner?

vetrano · Feb 22, 2016

jetsam said:
I see bricks with chips out of the surface, but maybe only 2 bricks below the roof that have cracks as opposed to cosmetic issues, and maybe 1 or 4 above the roof.

Why is anyone saying this should be rebuilt? (I believe you guys when you say there's a problem but I don't see it in the photos.)

What caused that interesting column of chipped bricks on the one side above the roof? Is that caused by the chimney leaning out over that corner?

Perhaps the photos don't do the full justice. Above the roof bricks on every other row are spalled on the south side and there are a few bricks on other sides that are also damaged. Below the roof there are probably 20-30 bricks that are either spalled or have cracks.

It has been suggested to me by everyone that this is water damage from water getting inside the bricks and then freeze/thaw cycles causing the bricks to crack/spall. I was told the south side is likely most damaged because any snow/ice can melt on sunny winter days and then refreeze at night.

I have been told that the damage I can see is the last stage of damage and many other bricks are likely in bad shape on the interior side. I'm no expert either, but I have heard this explanation by almost every mason I spoke with.

elmoleaf · Feb 22, 2016

There are some exceptionally wide vertical mortar joints in that structure. It makes one doubt the skill of whomever constructed it; it wouldnt be surprising if there are other hidden problems. It also appears like the chimney is not original to the house, given how poorly the brick is toothed into the facade in the second photo.
Sometimes this type of spalling occurs when a hard portland cement mortar is used with a soft brick, such as when modern mortar is used on historic masonry. The grade of mortar should always be softer than the brick. Ask the mason about this if you choose limited repairs.
I'd considered how quickly it took to get this bad and what percent of damage is below roofline. If rate of deterioration relatively slow and confined to top, you might consider limited rebuild unless the aesthetics bother you and you have money to spare.

jatoxico · Feb 22, 2016

vetrano said:
Also I'm planning to put a wood insert in. Given that the chimney needs at least a partial rebuild am I better off having it built with a clay flue liner and install a stainless liner inside of that or is there a better option?

If the chimney is only servicing the existing fireplace what about knocking it down and putting in a free standing stove and chimney. Off hand it sounds like it would be cheaper and you'd end up with a better heater.

vetrano · Feb 22, 2016

elmoleaf said:
There are some exceptionally wide vertical mortar joints in that structure. It makes one doubt the skill of whomever constructed it; it wouldnt be surprising if there are other hidden problems. It also appears like the chimney is not original to the house, given how poorly the brick is toothed into the facade in the second photo.
Sometimes this type of spalling occurs when a hard portland cement mortar is used with a soft brick, such as when modern mortar is used on historic masonry. The grade of mortar should always be softer than the brick. Ask the mason about this if you choose limited repairs.
I'd considered how quickly it took to get this bad and what percent of damage is below roofline. If rate of deterioration relatively slow and confined to top, you might consider limited rebuild unless the aesthetics bother you and you have money to spare.

Thanks for the feedback. If the visible damage below the roof is limited to 20-30 bricks would you expect the remaining bricks to be in good condition if all water issues are resolved (new chimney cap, flashing properly sealed, etc)?

Chimney is original to the 30 year old house. The mortar used in the house has eroded on the angled part of the fireplace as well as on window sills. Based on this I don't know that it is necessarily hard, but I'll ask about this as it is sounds plausible.

brickie · Feb 22, 2016

The wide head joints are due to the brick size.

elmoleaf · Feb 22, 2016

brickie said:
The wide head joints are due to the brick size.

It seems more likely the widely varying joints are because the mason didn't want to cut any bricks.
Ideal head joint would be 3/8", with variations in brick size resulting in head joints anywhere from 1/4" to 5/8". The layout could've been planned with cut bricks for a better final appearance and consistent head joints. Some of those head joints look almost 2" wide.

To the OP...it's really hard to offer advice based on three photos. However, 30 year old bricks shouldn't spall like that unless there was something wrong with the brick/mortar/installation or there's been no maintenance to the crown/top. At worst, after 30 years you'd expect maybe to need spot repointing of some mortar joints. Certainly having a proper crown with good drip edge to keep water from running down the brick face will help longevity. The photo is very blurry, but it doesn't seem like outer edge of the crown/cap has a drip cut. With surface tension, water is tenacious and will run right out over and back to the wall face below without a drip cut.
It seems the house wall protected by the roof eave isn't experiencing the same spalling, so I'm not sure the brick itself is entirely to blame.

In the 3rd picture, the capping bricks on the sloped masonry aren't ideal...it'd be better with the bricks installed as sailor course (wide face to the weather, with long direction pointing downhill) or a steeper pitch if the bricks are to be coursed like that. The current arrangement has lots of horizontal joints to collect water that needs to run off quickly, rather than collect in the joints.

It's hard to tell from the pics, but it doesn't seem like the mortar joint tooling is the problem. You want a concave or a weather-struck joint. Raked joints or anything like that will just allow water to collect and lead to problems.

Find a mason you trust. Ask to see some of his work, ideally similar repair jobs. Verify he is able to match both the brick type/color and mortar color/texture so spot repairs blend in seamlessly with the existing work.
PS. Brick window sills are a terrible construction detail for the reason you note....the mortar joints deteriorate relatively quickly and let water into the structure. Get those fixed too.

fire_man · Feb 23, 2016

elmoleaf said:
Sometimes this type of spalling occurs when a hard portland cement mortar is used with a soft brick, such as when modern mortar is used on historic masonry .

Why would too hard Portland cement used with soft brick lead to bricks spalling? I have heard not to use overly hard cement with historic structures but never understood why.

bholler · Feb 23, 2016

fire_man said:
Why would too hard Portland cement used with soft brick lead to bricks spalling? I have heard not to use overly hard cement with historic structures but never understood why.

Because brick and mortar is going to expand and contract when the mortar is harder that the brick when that brick expands the harder mortar will crush the brick little by little. this causes the face of that brick to fracture which lets water in and will eventually destroy that brick. Brick can also spall because of water infiltration for other reasons as well. Some bricks are also just not very good bricks we have some glen gery bricks in our area from the late 70s early 80s that all spall when exposed to the weather no mater what mortar is used.

warbonnet · Feb 23, 2016

Whatever you don't fix will potentially get water , freeze and continually get worse. I would be looking for a guarantee on any work done. Without seeing it first hand its tough to give an accurate opinion on which way to go.

bholler · Feb 23, 2016

warbonnet said:
Whatever you don't fix will potentially get water , freeze and continually get worse. I would be looking for a guarantee on any work done. Without seeing it first hand its tough to give an accurate opinion on which way to go.

No contractor in their right mind will give a guarantee on patching that. There are just to many unknowns

brickie · Feb 23, 2016

elmoleaf said:
It seems more likely the widely varying joints are because the mason didn't want to cut any bricks.
Ideal head joint would be 3/8", with variations in brick size resulting in head joints anywhere from 1/4" to 5/8". The layout could've been planned with cut bricks for a better final appearance and consistent head joints. Some of those head joints look almost 2" wide.

To the OP...it's really hard to offer advice based on three photos. However, 30 year old bricks shouldn't spall like that unless there was something wrong with the brick/mortar/installation or there's been no maintenance to the crown/top. At worst, after 30 years you'd expect maybe to need spot repointing of some mortar joints. Certainly having a proper crown with good drip edge to keep water from running down the brick face will help longevity. The photo is very blurry, but it doesn't seem like outer edge of the crown/cap has a drip cut. With surface tension, water is tenacious and will run right out over and back to the wall face below without a drip cut.
It seems the house wall protected by the roof eave isn't experiencing the same spalling, so I'm not sure the brick itself is entirely to blame.

In the 3rd picture, the capping bricks on the sloped masonry aren't ideal...it'd be better with the bricks installed as sailor course (wide face to the weather, with long direction pointing downhill) or a steeper pitch if the bricks are to be coursed like that. The current arrangement has lots of horizontal joints to collect water that needs to run off quickly, rather than collect in the joints.

It's hard to tell from the pics, but it doesn't seem like the mortar joint tooling is the problem. You want a concave or a weather-struck joint. Raked joints or anything like that will just allow water to collect and lead to problems.

Find a mason you trust. Ask to see some of his work, ideally similar repair jobs. Verify he is able to match both the brick type/color and mortar color/texture so spot repairs blend in seamlessly with the existing work.
PS. Brick window sills are a terrible construction detail for the reason you note....the mortar joints deteriorate relatively quickly and let water into the structure. Get those fixed too.

The brick used on this chimney are thin, that is to say the two heads and a normal joint don't equal a stretcher.
Sometimes when you notice a Very tight joint between stretchers and large joints on the opposite course, the Mason is kinda screwed by the material.
He can't cut the stretchers because he would have to cut all the opposite brick thin. The wrong size brick for a 16" pier. Having to wrap the flue with those brick are a problem.

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