Chimney construction

[swe13]

Hello
New to the forum and also having a chimney.

We are having the Crown replaced on our chimney and have a question on the construction of our chimney.

Chimney is large - 10 feet long and 2.5 feet wide and about 35 feet from the basement floor.

The crown has been removed, it was cracked and was only supported by rotten plywood.

My concern is that it is only single wide brick for most of the chimney with no support on the interior. 2 chimneys come up, one each side. Is the lack of support typical? Is this Ideal?

I've had 2 masonry companies come out, and neither seem overly concerned about it. I'm sure they know a lot more about chimneys than I, but it just seems like there should be some support in there.
I'll attach a few photos to show some detail.

Any insight would be greatly appreciated.

 

[bholler]

While i would like to see more support on a chimney that large it should be fine. And there is no good way to change it now anyway

 

[Destructor]

That isn’t bad, some masons would skimp on the concrete block surrounding the clay flues. Maybe consider installing some form of venting to allow moisture out of that masonry cavity, well screened to keep bugs and other critters out. It would be interesting to see how your masons build the form for the concrete cap.

 

[Seasoned Oak]

From what i understand the flue needs to be able to expand a little so it dont crack mostly vertically.

 

[bholler]

From what i understand the flue needs to be able to expand a little so it dont crack mostly vertically.

Yes but in this case the flues are in their own block structures inside a much larger brick structure.

 

[Jo191145]

Yes there should have been support walls inside that void to close over with 4" cement blocks.
I would demand cement board be used to close over. Double thick. NO Plywood.

 

[bholler]

Yes there should have been support walls inside that void to close over with 4" cement blocks.
I would demand cement board be used to close over. Double thick. NO Plywood.

We use sheet metal to support the concrete till it sets up. I hope they are doing a poured overhanging crown.

 

[Jo191145]

We use sheet metal to support the concrete till it sets up. I hope they are doing a poured overhanging crown.

I would worry about the steel rusting and turning the chimney orange over the years
A poured crown does
Go a long way to alleviate that worry

 

[bholler]

I would worry about the steel rusting and turning the chimney orange over the years
A poured crown does
Go a long way to alleviate that worry

There is no metal exposed so we have never had an issue

 

[swe13]

I posted this with the pictures above, but the text didn't post for some reason.
Thanks for the replies. The lowest bid we had was $6,500. Since I have more time than money we decided to replace the crown ourselves. We used angle iron for supports similar to this https://www.hearth.com/talk/threads/new-chimney-crown-my-experience.53050/ but with a lot more angle iron. We used 2x4's with a 15* slope to create a sloped overhang. As suggested by bholler and a couple other articles we used galvanized sheet metal to close over. We used 2" mesh and 3/8" rebar (someone is going to be cursing me in the future) Total cost was under $200 for the fiber reinforced concrete, mesh, rebar and sheet metal. I also did an elastomeric coating (mainly because I already had it - originally planned on just recoating the old crown) Total was about 35-40 man hours. It adds up quick when you have your 3 brothers(moe larry and curly) mixing concrete and lifting it up 40 feet. Glad its done, and I expect it to last quite a while.

 

[bholler]

I posted this with the pictures above, but the text didn't post for some reason.
Thanks for the replies. The lowest bid we had was $6,500. Since I have more time than money we decided to replace the crown ourselves. We used angle iron for supports similar to this https://www.hearth.com/talk/threads/new-chimney-crown-my-experience.53050/ but with a lot more angle iron. We used 2x4's with a 15* slope to create a sloped overhang. As suggested by bholler and a couple other articles we used galvanized sheet metal to close over. We used 2" mesh and 3/8" rebar (someone is going to be cursing me in the future) Total cost was under $200 for the fiber reinforced concrete, mesh, rebar and sheet metal. I also did an elastomeric coating (mainly because I already had it - originally planned on just recoating the old crown) Total was about 35-40 man hours. It adds up quick when you have your 3 brothers(moe larry and curly) mixing concrete and lifting it up 40 feet. Glad its done, and I expect it to last quite a while.

Looks good my only concern is how long did you wait before coating it?

 

[Seasoned Oak]

Nice!

 

[swe13]

Looks good my only concern is how long did you wait before coating it?

Approximately 2 weeks. Read somewhere (instructions or website) that they said to wait 3 days. It is supposed to be 100% vapor permeable so shouldn't trap any moisture from the curing concrete.

 

[swe13]

Now I just need to figure out what to do about the flashing around the chimney... it is HORRIBLE to say the least. The block and brick at the level of the saddle sticks out up to an inch or more further than the chimney. It was never counterflashed and quite honestly I don't know how there isn't more damage on the inside of the house. I'm debating if I should grind the block/brick/mortar until it is flush with the rest of the chimney and then properly flash and counterflash, or if I can get by with just counterflashing and sealing.

 

[bholler]

Now I just need to figure out what to do about the flashing around the chimney... it is HORRIBLE to say the least. The block and brick at the level of the saddle sticks out up to an inch or more further than the chimney. It was never counterflashed and quite honestly I don't know how there isn't more damage on the inside of the house. I'm debating if I should grind the block/brick/mortar until it is flush with the rest of the chimney and then properly flash and counterflash, or if I can get by with just counterflashing and sealing.View attachment 201677 View attachment 201678 View attachment 201679 View attachment 201680 View attachment 201681

Yeah you need counter flashing cut into the brick

 

[bholler]

Approximately 2 weeks. Read somewhere (instructions or website) that they said to wait 3 days. It is supposed to be 100% vapor permeable so shouldn't trap any moisture from the curing concrete.

Good

 

[armanidog]

About the flashing. You could attach counter flashing directly on the brick face and then stucco the exposed chimney column.
Here is a quick video on stuccoing a brick chimney, it has a 15 second ad at the beginning. I had mine stuccoed since the bricks were made locally in 1906 and had started deteriorating. The mason added new counter flashing before the stucco was put on. The nice thing is you can use a coloring agent for the final coat if desired.
http://www.diynetwork.com/videos/stucco-brick-chimney-makeover-0207913

 

[bholler]

About the flashing. You could attach counter flashing directly on the brick face and then stucco the exposed chimney column.
Here is a quick video on stuccoing a brick chimney, it has a 15 second ad at the beginning. I had mine stuccoed since the bricks were made locally in 1906 and had started deteriorating. The mason added new counter flashing before the stucco was put on. The nice thing is you can use a coloring agent for the final coat if desired.
http://www.diynetwork.com/videos/stucco-brick-chimney-makeover-0207913

Yes you could do that but why in his case? Just cut the flashing in like normal.

 

[swe13]

Yeah you need counter flashing cut into the brick

What would you do about the block and mortar that is extended past the rest of the chimney? grind it flush and try to fix the step flashing, leave it as is and caulk the heck out of it before installing the counterflasing, or something else?

 

[bholler]

What would you do about the block and mortar that is extended past the rest of the chimney? grind it flush and try to fix the step flashing, leave it as is and caulk the heck out of it before installing the counterflasing, or something else?

Get out as much as you can so the step sits as flat as possible then counterflash. And no don't caulk the heck out of anything a good flashing job should never rely on caulk

 

[Seasoned Oak]

Get out as much as you can so the step sits as flat as possible then counterflash. And no don't caulk the heck out of anything a good flashing job should never rely on caulk

You would be surprised how many chimneys are not flashed at all, just caulked and the caulk is always cracked and leaking. Not sure if its the chimney installer of the roofers fault or both.

 

[bholler]

You would be surprised how many chimneys are not flashed at all, just caulked and the caulk is always cracked and leaking. Not sure if its the chimney installer of the roofers fault or both.

No I would not be surprised. I work on chimneys every day I know very well that a large percentage are not flashed properly. Many not at all

 

[BlankBlankBlank]

As bholler said, get that stuff out from behind the step flashing. It might go easy or might be tedious. But take the time to get it out.

 

[Woody Stover]

]I posted this with the pictures above, but the text didn't post for some reason.

Nice!

I work on chimneys every day I know very well that a large percentage are not flashed properly. Many not at all

I can understand a hack like me taking some shortcuts here and there, but a "pro?" C'mon. BTW, on my recent re-roof, even I did the flashing right. Sheesh, it ain't that hard.

 

[bholler]

Nice! I can understand a hack like me taking some shortcuts here and there, but a "pro?" C'mon. BTW, on my recent re-roof, even I did the flashing right. Sheesh, it ain't that hard.

Yeah I don't know why roofers don't seem to be able to do it right