I need help understanding my predicament. New crown poured by pro, should there be a flue tile expansion joint?

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dbwa

New Member
Dec 28, 2022
4
Washington
TLDR: Should my chimney crown have an expansion joint between the flue tile and the concrete crown? (Photos at the bottom)

Longer version
My wife and I are first time homeowners in the PNW. We have had a few power outages and wanted to prepare our chimney/fireplace for an insert. As part of getting our chimney swept we were told that our chimney crown needed to be replaced due to cracks forming in the crown and the threat of water infiltration. We decided that replacing the crown and some flashing is better to do now than replacing the chimney later. Since the chimney sweep admitted to being new in the trade (less than 2 years) we decided to seek out a more experienced company to do the work.

We hired a CSIA certified chimney sweep company to pour a new crown. Before they started their work I had a few questions about my experience using the fire place, and when they technician looked in my fireplace he told me that he thought we needed a PCR cleaning ($2000) and a spray in parging ($1200) on top of the new crown and new flashing they were installing that day. I felt a bit like they were trying to turn a $3100 job into a $6300 job. They finished up a little after dark and told me they'd come get their forms in about 7 days.

The morning after they finished I went up on the roof to see the work they had done and noticed that they hadn't left an expansion joint around the flue tile. I felt around the base of the tile and didn't feel a seem around the flue. In the photos the flue on the left is the wood burning fire place and the flue on the right is a gas flue. The wood burning fireplace flue is maybe 14" across. I have a couple of questions:

1) Are expansion joints around flue tiles in the crown standard practice?
2) Is it possible the expansion joint is below the concrete surface? (When I felt the seem with my fingers I couldn't detect anything other than concrete going right up to the flue tile)
3) Is this something that is cut in after they remove the form and seal up with a special kind of caulking?

Really looking for some help here so I can figure out how to follow up with the company when they come back to get their forms.

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I don't think they put an expansion joint between the tile and the crown. I caulked that joint when I did mine, though..
 
I think the expansion joint in concrete is just to allow the concrete to crack while looking neat on the top side.
 
I think the expansion joint in concrete is just to allow the concrete to crack while looking neat on the top side.
No it's to keep the crown from cracking when the clay liner expands. Without one either the crown will crack or the clay will crush itself
 
Just curious; what would be a suitable material to allow for expansion? Or just use an airspace to be flashed and/or caulked after the fact?
 
Just curious; what would be a suitable material to allow for expansion? Or just use an airspace to be flashed and/or caulked after the fact?
I use sill seal foam. Then pull it out and seal the gap with silicone
 
I use sill seal foam. Then pull it out and seal the gap with silicone
Thinking more about it, I seem to remember using some pink sheet stuff around the liners. Maybe it was sill seal..?
 
Thinking more about it, I seem to remember using some pink sheet stuff around the liners. Maybe it was sill seal..?
Probably. Most of the stuff I use is pink
 
@bholler why wouldn't sill seal melt where it touches the flue? Or is it the case that the melting doesn't matter? The professional I'm working with seems reticent to use sill seal due to melting and thinks that in the PNW climate the gap will be too much of a water leak risk. Is there a different material that also works well, and if so can you point me to a product link online (or product name?)?
 
@bholler why wouldn't sill seal melt where it touches the flue? Or is it the case that the melting doesn't matter? The professional I'm working with seems reticent to use sill seal due to melting and thinks that in the PNW climate the gap will be too much of a water leak risk. Is there a different material that also works well, and if so can you point me to a product link online (or product name?)?
Yes that's why I pull it out after the concrete sets. I really don't think it would matter most guys don't and it's not an issue. But it's easy to do if you wrap it in stretch wrap.

And yes it is a slight leak risk if not resealed occasionally. But a cracked crown caused by the lack of an expansion joint will absolutely crack.

Tell the mason to check the brick institute of America's recommendations for crowns.
 
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TLDR: Should my chimney crown have an expansion joint between the flue tile and the concrete crown? (Photos at the bottom)

Longer version
My wife and I are first time homeowners in the PNW. We have had a few power outages and wanted to prepare our chimney/fireplace for an insert. As part of getting our chimney swept we were told that our chimney crown needed to be replaced due to cracks forming in the crown and the threat of water infiltration. We decided that replacing the crown and some flashing is better to do now than replacing the chimney later. Since the chimney sweep admitted to being new in the trade (less than 2 years) we decided to seek out a more experienced company to do the work.

We hired a CSIA certified chimney sweep company to pour a new crown. Before they started their work I had a few questions about my experience using the fire place, and when they technician looked in my fireplace he told me that he thought we needed a PCR cleaning ($2000) and a spray in parging ($1200) on top of the new crown and new flashing they were installing that day. I felt a bit like they were trying to turn a $3100 job into a $6300 job. They finished up a little after dark and told me they'd come get their forms in about 7 days.

The morning after they finished I went up on the roof to see the work they had done and noticed that they hadn't left an expansion joint around the flue tile. I felt around the base of the tile and didn't feel a seem around the flue. In the photos the flue on the left is the wood burning fire place and the flue on the right is a gas flue. The wood burning fireplace flue is maybe 14" across. I have a couple of questions:

1) Are expansion joints around flue tiles in the crown standard practice?
2) Is it possible the expansion joint is below the concrete surface? (When I felt the seem with my fingers I couldn't detect anything other than concrete going right up to the flue tile)
3) Is this something that is cut in after they remove the form and seal up with a special kind of caulking?

Really looking for some help here so I can figure out how to follow up with the company when they come back to get their forms.

View attachment 306616 View attachment 306617
Absolutely nothing to get nervous about. If anything over time a gap will show between the 2. Some sill sealer isn't a bad initial idea at all but as the concrete continues to cure over the decades, the gap will have to be monitored and caulked.
Looks like a nice pour.
 
Absolutely nothing to get nervous about. If anything over time a gap will show between the 2. Some sill sealer isn't a bad initial idea at all but as the concrete continues to cure over the decades, the gap will have to be monitored and caulked.
Looks like a nice pour.
I am sorry but without an expansion joint the expansion of the clay will crack the crown. I see it hundreds of times a year.
 
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I am sorry but without an expansion joint the expansion of the clay will crack the crown. I see it hundreds of times a year.
Just wanted to chime in here that I had a new crown poured last October (2021) and they didn’t put an expansion joint. Guess what? It’s cracking. Will be adding that to my list of chimney work.

8C261E0E-81BD-4AF2-BDF9-60B6BAB25D4C.jpeg
 
Just wanted to chime in here that I had a new crown poured last October (2021) and they didn’t put an expansion joint. Guess what? It’s cracking. Will be adding that to my list of chimney work.

View attachment 309074
I shoulda looked closer when I removed the old crown. It was cracked but I don't recall if there was a gap between the crown and the tile liner. It was original, 1940, so maybe it was going to be cracked anyway, even with the gap, I don't know.
I wonder what a good way is to repair that? Use a masonry wheel on an angle grinder to establish a gap between the crown and liner?
Then chip the crack in the crown wider with a chisel (or the grinding wheel,) and then seal that?
 
I shoulda looked closer when I removed the old crown. It was cracked but I don't recall if there was a gap between the crown and the tile liner. It was original, 1940, so maybe it was going to be cracked anyway, even with the gap, I don't know.
I wonder what a good way is to repair that? Use a masonry wheel on an angle grinder to establish a gap between the crown and liner?
Then chip the crack in the crown wider with a chisel (or the grinding wheel,) and then seal that?
My whole chimney above the roofline needs to be repointed, and I have some rows of brick that are starting to spall. My bricks get saturated really easily and I’m sure it’s leaking behind the tile. You can see moss in the photo that I later picked off. So, when I do that I’m going to have them build a proper crown entirely. It just sucks that I paid for a company to do this and it cracked a year later. There’s some real crap chimney companies out there, even ones that are very positively reviewed. Frankly, I don’t think people know what to look for. I wouldn’t if it wasn’t for this forum!
 
Just wanted to chime in here that I had a new crown poured last October (2021) and they didn’t put an expansion joint. Guess what? It’s cracking. Will be adding that to my list of chimney work.

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That sucks but not surprising
 
have some rows of brick that are starting to spall. ....when I do that I’m going to have them build a proper crown entirely. It just sucks that I paid for a company to do this and it cracked a year later. There’s some real crap chimney companies out there, even ones that are very positively reviewed.
I heard that. I called a couple places first. They were pricey, and I'm leery of all contractors...anything I've had done has been hack work to some extent.
So I decided I'd have a go at it. It isn't too hard, but getting the 'crete up there is a chore. I guess that can be done on the roof but I don't know too much about it.
I replaced five courses of brick. Even though the old crown had an overhang, those top bricks were spalled and cracked.
I found a video on how to re-crown, and one thing he provided for was a drip edge on the underside of the crown to keep some water off the brick.
Actually, I was guilty of a bit of hack work on the concrete. It was cold fall weather so I tented the crown and had a hair dryer blowing up under there to help cure it. 😏 It was hard getting the 'crete mixed and up on the roof in a timely fashion, working with two guys who didn't know much. I could also see, when I removed the form, that some of the 'crete was either not mixed thoroughly enough, or not quite shoved into a corner of the form completely, or it got dry or whatever. I used the fiber 'crete, and the right type for the job, so it'll be interesting to see how long it holds up. Or it could be annoying to see that. 😆
Overall, I was pretty happy with how I did, being a rookie and all. I thought I did a decent job on the roof and flashing.. 👉
I tried to find the video I followed on crown replacement, but couldn't find it so far. It was very good. Some of the ones you watch, even someone inexperienced like me can tell it's bogus information. 😒

crown.JPGcrown3.JPG
 
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Looks like you did a good job on the bricks and the crown.
I've done (bad) DIY bricklaying before and it can be a challenge.
 
I heard that. I called a couple places first. They were pricey, and I'm leery of all contractors...anything I've had done has been hack work to some extent.
So I decided I'd have a go at it. It isn't too hard, but getting the 'crete up there is a chore. I guess that can be done on the roof but I don't know too much about it.
I replaced five courses of brick. Even though the old crown had an overhang, those top bricks were spalled and cracked.
I found a video on how to re-crown, and one thing he provided for was a drip edge on the underside of the crown to keep some water off the brick.
Actually, I was guilty of a bit of hack work on the concrete. It was cold fall weather so I tented the crown and had a hair dryer blowing up under there to help cure it. 😏 It was hard getting the 'crete mixed and up on the roof in a timely fashion, working with two guys who didn't know much. I could also see, when I removed the form, that some of the 'crete was either not mixed thoroughly enough, or not quite shoved into a corner of the form completely, or it got dry or whatever. I used the fiber 'crete, and the right type for the job, so it'll be interesting to see how long it holds up. Or it could be annoying to see that. 😆
Overall, I was pretty happy with how I did, being a rookie and all. I thought I did a decent job on the roof and flashing.. 👉
I tried to find the video I followed on crown replacement, but couldn't find it so far. It was very good. Some of the ones you watch, even someone inexperienced like me can tell it's bogus information. 😒

View attachment 309079View attachment 309080
Damn, dude. For a rookie that looks pretty damn good. Much better than half the crap I see in my neighborhood even after repairs by “professionals”. I repointed some of the brick in my attic space as a little trial and let’s just say I will not be trying it outside lol. I see you had some scaffolding up; at least you had a platform. To get to my chimney I have to climb out a dormer window, say a little prayer, and scoot my way up the roof like a spider
 
Looks like you did a good job on the bricks and the crown.
I've done (bad) DIY bricklaying before and it can be a challenge.
I see you had some scaffolding up; at least you had a platform. To get to my chimney I have to climb out a dormer window, say a little prayer, and scoot my way up the roof like a spider
I think I was using a level to make sure I was staying more or less flat.
But as I said, working efficiently and quickly was a challenge when I had to keep stopping and thinking about stuff. Then my OCD kicked in on the brick joints and I had to try to smoothe them all in with a little tool I had bought, to make them look pretty. But looking at the rest of the creo-soaked chimbley, what was the point?? 😆 In the meantime the 'crete wasn't waiting for me, kept drying out, etc.
Thinking back, I mixed the brick mortar in a big tray, up on the scaffold, but did the crown mix on the ground in a power mixer, with my nephew staying on the ground and me pulling up the 'crete with a rope and five-gallon bucket and emptying it into the wooden crown form.
 
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