Stainless cover vs full chimney cap over masonry crown

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Kvic

New Member
Sep 12, 2021
50
Middle Tn
Hope those of you with experience can shed some light. After a recent insert install, realized the chimney was leaking. Crown has some cracks but otherwise solid. Mortar joints were needing some help too. Have gotten several estimates for repointing and crown repair. None of the estimates included re-pouring a new crown. All the estimates include sealing the crown with Crown Seal, and 2 recommended full chimney cap.
When I first looked at the chimney, I started looking into what things I might be able to do myself, and from reading through some of the posts was looking at having a stainless cover made. I mentioned that option to an estimator today, and he said they don't recommend it because it will cause moisture to get trapped causing condensation that will rot out the crown. Don't know if the region makes a difference, but after reading some posts on here where some have installed the covers, was wondering if his statement was valid. The full caps are about 3 times the cost of the cover plus another $200 for installation, and that's for powder coated galvanized. Chimney is 26x72 inches with 2 flues.
 

begreen

Mooderator
Staff member
Nov 18, 2005
89,766
South Puget Sound, WA
I wouldn't expect a properly made and installed crown cap to trap major moisture. It should stay quite dry under there. If that is the route to be taken, consider stainless steel.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
25,654
central pa
Hope those of you with experience can shed some light. After a recent insert install, realized the chimney was leaking. Crown has some cracks but otherwise solid. Mortar joints were needing some help too. Have gotten several estimates for repointing and crown repair. None of the estimates included re-pouring a new crown. All the estimates include sealing the crown with Crown Seal, and 2 recommended full chimney cap.
When I first looked at the chimney, I started looking into what things I might be able to do myself, and from reading through some of the posts was looking at having a stainless cover made. I mentioned that option to an estimator today, and he said they don't recommend it because it will cause moisture to get trapped causing condensation that will rot out the crown. Don't know if the region makes a difference, but after reading some posts on here where some have installed the covers, was wondering if his statement was valid. The full caps are about 3 times the cost of the cover plus another $200 for installation, and that's for powder coated galvanized. Chimney is 26x72 inches with 2 flues.
A chase cover is ok but absolutely nowhere near as good as a properly poured crown.
 

Bad LP

Minister of Fire
Nov 28, 2014
1,736
Northern Maine
Having a SS cap made right now while the crown is in great shape.
37x39 w/ 3 flues.
 

Sawset

Minister of Fire
Feb 14, 2015
1,203
Palmyra, WI
I would consider a stainless cap as permanent. A galvanized cap would have a 25yr life span - maybe more depending on the climate , and also tolerance of how rust colored the siding becomes. Galvanized caps from 30 years ago, those are currently in the process of being replaced. The price point at the time was attractive, as long as the maintenance issues could be deferred.
 

Kvic

New Member
Sep 12, 2021
50
Middle Tn
I wouldn't expect a properly made and installed crown cap to trap major moisture. It should stay quite dry under there. If that is the route to be taken, consider stainless steel.
I'm considering the stainless chase covers from Rockford. The current crown is about 2 1/2 inches with slope, so I would assume the only part of the chase touching concrete would be right around the flue tiles leaving some space for air circulation. The down side is it would need about a 5" skirt to reach the top row of brick to tapcon into, so considering having it powder coated as well to blend a little better.
 

Kvic

New Member
Sep 12, 2021
50
Middle Tn
A chase cover is ok but absolutely nowhere near as good as a properly poured crown.
That definitely seems to be the consensus from reading through older posts. Trying to work within a budget is making me look at other alternatives, and diy options.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
25,654
central pa
That definitely seems to be the consensus from reading through older posts. Trying to work within a budget is making me look at other alternatives, and diy options.
I certainly understand that but I would absolutely avoid galvanized even if powder coated.
 

Kvic

New Member
Sep 12, 2021
50
Middle Tn
I certainly understand that but I would absolutely avoid galvanized even if powder coated.
I would definitely prefer SS over galvanized for a cap, but know that would add even more to the cost.
ls a poured crown something a diyer should attempt or best left to the pro's?
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
25,654
central pa
I would definitely prefer SS over galvanized for a cap, but know that would add even more to the cost.
ls a poured crown something a diyer should attempt or best left to the pro's?
Sure it can absolutely be done diy. It isn't complicated and the materials are cheap. It's just allot is manual labor
 

armanidog

Feeling the Heat
Jan 8, 2017
283
Northeast Georgia
I would definitely prefer SS over galvanized for a cap, but know that would add even more to the cost.
ls a poured crown something a diyer should attempt or best left to the pro's?
What pitch is your roof? If you have shingles put down some protection like plywood to avoid damage. If its metal be very careful. The least bit of moisture could have you sliding around.
 

Kvic

New Member
Sep 12, 2021
50
Middle Tn
What pitch is your roof? If you have shingles put down some protection like plywood to avoid damage. If its metal be very careful. The least bit of moisture could have you sliding around.
Thanks for the video, that was where I was headed next. The pitch isn't too bad, somewhere in the 6-8/12 range, and it's internal so no need for scaffolding. I'll post some pictures that show the condition of the chimney in a bit.
 

Kvic

New Member
Sep 12, 2021
50
Middle Tn
Here are some pics of the chimney. House was built in 1965, so don't know if this would all be original crown or not. Roof and flashing were redone about 6 years ago, and we've been in it just over 2 years. If it wasn't for a cracked sinking patio that needs attention as well, we could do either as estimated, but in order to do both, I'll need to do some things myself. Oh, only one flue is active, the other is filled in.

All the quotes included pressure washing, crown seal, repointing (doing mortar joint on cracked bricks, or replace but won't match), waterproofing, and re-caulking flashing.

My one concern with the SS chase cover is the size of the skirt needed. My concerns on first thoughts of redoing the crown with a poured crown are possibly dislodging/damaging the top row of brick, or damaging the flue liners.

IMG_3359.jpg IMG_3360.jpg IMG_3361.jpg IMG_3362.jpg IMG_3363.jpg IMG_3365.jpg IMG_3388.jpg
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
25,654
central pa
Here are some pics of the chimney. House was built in 1965, so don't know if this would all be original crown or not. Roof and flashing were redone about 6 years ago, and we've been in it just over 2 years. If it wasn't for a cracked sinking patio that needs attention as well, we could do either as estimated, but in order to do both, I'll need to do some things myself. Oh, only one flue is active, the other is filled in.

All the quotes included pressure washing, crown seal, repointing (doing mortar joint on cracked bricks, or replace but won't match), waterproofing, and re-caulking flashing.

My one concern with the SS chase cover is the size of the skirt needed. My concerns on first thoughts of redoing the crown with a poured crown are possibly dislodging/damaging the top row of brick, or damaging the flue liners.

View attachment 282133 View attachment 282134 View attachment 282135 View attachment 282136 View attachment 282137 View attachment 282138 View attachment 282139
You will without a doubt end up relaying some brick no way around that. You also need quite a bit of repointing done. I would repoint the whole thing honestly. If you damage the tile just replace them
 

Kvic

New Member
Sep 12, 2021
50
Middle Tn
You will without a doubt end up relaying some brick no way around that. You also need quite a bit of repointing done. I would repoint the whole thing honestly. If you damage the tile just replace them
I had mentioned repointing the whole thing to one of the estimators, but they said only parts needed to be done. Seems like it would look better if all of it was done. You make it sound so easy, that there's a big part of me that's ready to get my hands dirty with all of it, but knowing me, nothing ends up being as easy at it seems. That's why I was considering the chase cover route. Hire someone to repoint, and install the cover myself. Less room for error, unless I measure wrong for the cover. But, the poured crown looks a whole lot better.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
25,654
central pa
I had mentioned repointing the whole thing to one of the estimators, but they said only parts needed to be done. Seems like it would look better if all of it was done. You make it sound so easy, that there's a big part of me that's ready to get my hands dirty with all of it, but knowing me, nothing ends up being as easy at it seems. That's why I was considering the chase cover route. Hire someone to repoint, and install the cover myself. Less room for error, unless I measure wrong for the cover. But, the poured crown looks a whole lot better.
I never said it was easy. For me it is but I have been doing this a long time.
 

Kvic

New Member
Sep 12, 2021
50
Middle Tn
I never said it was easy. For me it is but I have been doing this a long time.
Yeah, I knew you were talking from your experience, which is why I knew I wouldn't experience the same thing.

Not afraid of hard work, or attempting a new task I've never done as long as I know I can't make it worse, or cost more in the long run.
 

begreen

Mooderator
Staff member
Nov 18, 2005
89,766
South Puget Sound, WA
Kvic, this thread will give you an idea of what is involved with pouring a crown.
 
I am a commercial masonry contractor. My guys make a killing repairing chimney crowns on weekends. Knowing what I know about the performance of mortar and concrete in a horizontal unreinforced application as well as the way that brick and concrete's expansion properties are in opposition to one another I wanted nothing to do with that on my own house when I installed my insert. I used a stainless chase cover and I would never do it any other way on my own house.

That being said if I were to install your chimney crown i would first dig out all the bad joints and retuck with pointing mortar. That projected fourth course from the top is an extremely common and extremely terrible detail. I had something similar on mine. I installed a 45 degree mortar wash on top of mine so that it would shed water and snow. Whenever you work with new mortar on existing work it is always a good idea to dampen the existing masonry to encourage a strong bond. An additional bonding agent doesn't hurt either. I cut my clay liner flush and after all repairs to the masonry are complete give it a thorough soaking with a strong mixture of siloxane (a breathable waterproof masonry sealant that should last at least 15 years). My house has a pourous southern brick, the type a mason hates to lay because they have to joint their work after every couple of brick. I may skip the sealer on a high quality brick out of northern Ohio. If you are certain that you will have no future use for the second flue I would cut it flush and spring a piece of hardware cloth into it and seal it off to the top with a few solid brick and slick off the top and seal it from the bottom as well.

I would order a chase cover with only one hole for the flue in use and make sure it is pitched in all directions away from said hole. Make the opening 3/4" bigger than the outside diameter of the liner. The extra cost for heavier guage was well worth it in my opinion. Mine was well made even though it was slightly "sprung". That was easily corrected during the install which involved shims and tap cons on the 4 sides of the chimney through the four inch skirt which with the flared drip edge sends water far down the masonry prior to contact in most circumstances.

The kit I bought from Rockford had a very nice termination peice for the top of the liner that slid up inside a slightly domed top plate that was designed to be tap conned into the masonry crown. I screwed this top plate down to the chase cover with short stainless self tappers with neoprene washers. I tightened everything together in a very generous bed of silicone. Finally the rain cap slid over the top plate so that everything "shingled" properly.

Realistically, this crown should outlast the stove and the liner and the next one and the next liner after that. The way I installed it I should never have to address any maintenance beyond a little scraping away and reapplying silicone on the stainless self tappers every ten years or so. Even that is a fail safe considering there are neoprene washers at play as well as an intact mortar crown below.

304 stainless is wonderful stuff. I have drums of anchors made of it from old jobs sitting in the woods behind my shop from 25 years ago and the rust stains from the drums can be wiped off with a paper towel and they look like we took delivery of them yesterday. Short of a salt water application I would assume it will outlast any of us and our grandkids.

This is merely my best idea to future proof a chimney crown for an extremely low cost.

20200927_153216.jpg 20200927_153214.jpg 20200927_153211.jpg
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
25,654
central pa
I am a commercial masonry contractor. My guys make a killing repairing chimney crowns on weekends. Knowing what I know about the performance of mortar and concrete in a horizontal unreinforced application as well as the way that brick and concrete's expansion properties are in opposition to one another I wanted nothing to do with that on my own house when I installed my insert. I used a stainless chase cover and I would never do it any other way on my own house.

That being said if I were to install your chimney crown i would first dig out all the bad joints and retuck with pointing mortar. That projected fourth course from the top is an extremely common and extremely terrible detail. I had something similar on mine. I installed a 45 degree mortar wash on top of mine so that it would shed water and snow. Whenever you work with new mortar on existing work it is always a good idea to dampen the existing masonry to encourage a strong bond. An additional bonding agent doesn't hurt either. I cut my clay liner flush and after all repairs to the masonry are complete give it a thorough soaking with a strong mixture of siloxane (a breathable waterproof masonry sealant that should last at least 15 years). My house has a pourous southern brick, the type a mason hates to lay because they have to joint their work after every couple of brick. I may skip the sealer on a high quality brick out of northern Ohio. If you are certain that you will have no future use for the second flue I would cut it flush and spring a piece of hardware cloth into it and seal it off to the top with a few solid brick and slick off the top and seal it from the bottom as well.

I would order a chase cover with only one hole for the flue in use and make sure it is pitched in all directions away from said hole. Make the opening 3/4" bigger than the outside diameter of the liner. The extra cost for heavier guage was well worth it in my opinion. Mine was well made even though it was slightly "sprung". That was easily corrected during the install which involved shims and tap cons on the 4 sides of the chimney through the four inch skirt which with the flared drip edge sends water far down the masonry prior to contact in most circumstances.

The kit I bought from Rockford had a very nice termination peice for the top of the liner that slid up inside a slightly domed top plate that was designed to be tap conned into the masonry crown. I screwed this top plate down to the chase cover with short stainless self tappers with neoprene washers. I tightened everything together in a very generous bed of silicone. Finally the rain cap slid over the top plate so that everything "shingled" properly.

Realistically, this crown should outlast the stove and the liner and the next one and the next liner after that. The way I installed it I should never have to address any maintenance beyond a little scraping away and reapplying silicone on the stainless self tappers every ten years or so. Even that is a fail safe considering there are neoprene washers at play as well as an intact mortar crown below.

304 stainless is wonderful stuff. I have drums of anchors made of it from old jobs sitting in the woods behind my shop from 25 years ago and the rust stains from the drums can be wiped off with a paper towel and they look like we took delivery of them yesterday. Short of a salt water application I would assume it will outlast any of us and our grandkids.

This is merely my best idea to future proof a chimney crown for an extremely low cost.

View attachment 282193 View attachment 282194 View attachment 282195
Very good advice on pointing but as far as a poured crown goes it should always be done with fiber reinforced concrete and there should always be a bond break between the chimney and crown. And an expansion joint around the liners. Without that it isn't a proper crown and it won't hold up well.

I also will never permanently close off a flue. Infact I really try to never completely seal one. I have found it is much better to allow a little air flow through unused flues. And no matter what someone thinks now they may want to use that flue at a later point.
 

Kvic

New Member
Sep 12, 2021
50
Middle Tn
Kvic, this thread will give you an idea of what is involved with pouring a crown.
Thanks begreen. I must be doing searches wrong because I don't remember reading through that one. Good tip in there on the air hammer.
 

Kvic

New Member
Sep 12, 2021
50
Middle Tn
I am a commercial masonry contractor. My guys make a killing repairing chimney crowns on weekends. Knowing what I know about the performance of mortar and concrete in a horizontal unreinforced application as well as the way that brick and concrete's expansion properties are in opposition to one another I wanted nothing to do with that on my own house when I installed my insert. I used a stainless chase cover and I would never do it any other way on my own house.

That being said if I were to install your chimney crown i would first dig out all the bad joints and retuck with pointing mortar. That projected fourth course from the top is an extremely common and extremely terrible detail. I had something similar on mine. I installed a 45 degree mortar wash on top of mine so that it would shed water and snow. Whenever you work with new mortar on existing work it is always a good idea to dampen the existing masonry to encourage a strong bond. An additional bonding agent doesn't hurt either. I cut my clay liner flush and after all repairs to the masonry are complete give it a thorough soaking with a strong mixture of siloxane (a breathable waterproof masonry sealant that should last at least 15 years). My house has a pourous southern brick, the type a mason hates to lay because they have to joint their work after every couple of brick. I may skip the sealer on a high quality brick out of northern Ohio. If you are certain that you will have no future use for the second flue I would cut it flush and spring a piece of hardware cloth into it and seal it off to the top with a few solid brick and slick off the top and seal it from the bottom as well.

I would order a chase cover with only one hole for the flue in use and make sure it is pitched in all directions away from said hole. Make the opening 3/4" bigger than the outside diameter of the liner. The extra cost for heavier guage was well worth it in my opinion. Mine was well made even though it was slightly "sprung". That was easily corrected during the install which involved shims and tap cons on the 4 sides of the chimney through the four inch skirt which with the flared drip edge sends water far down the masonry prior to contact in most circumstances.

The kit I bought from Rockford had a very nice termination peice for the top of the liner that slid up inside a slightly domed top plate that was designed to be tap conned into the masonry crown. I screwed this top plate down to the chase cover with short stainless self tappers with neoprene washers. I tightened everything together in a very generous bed of silicone. Finally the rain cap slid over the top plate so that everything "shingled" properly.

Realistically, this crown should outlast the stove and the liner and the next one and the next liner after that. The way I installed it I should never have to address any maintenance beyond a little scraping away and reapplying silicone on the stainless self tappers every ten years or so. Even that is a fail safe considering there are neoprene washers at play as well as an intact mortar crown below.

304 stainless is wonderful stuff. I have drums of anchors made of it from old jobs sitting in the woods behind my shop from 25 years ago and the rust stains from the drums can be wiped off with a paper towel and they look like we took delivery of them yesterday. Short of a salt water application I would assume it will outlast any of us and our grandkids.

This is merely my best idea to future proof a chimney crown for an extremely low cost.

View attachment 282193 View attachment 282194 View attachment 282195
Thanks for the detailed write up doublebogey. I was thinking about taking out that second flue, since it doesn't appear to go anywhere unless there is a hidden fireplace opening behind the kitchen wall on the other side. On top it's completely filled with concrete, and one of the estimators thought it was just put there for aesthetics. Most of the houses in the neighborhood have similar chimney structures, and most have a second flue but only one cap like ours was originally.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
25,654
central pa
Thanks for the detailed write up doublebogey. I was thinking about taking out that second flue, since it doesn't appear to go anywhere unless there is a hidden fireplace opening behind the kitchen wall on the other side. On top it's completely filled with concrete, and one of the estimators thought it was just put there for aesthetics. Most of the houses in the neighborhood have similar chimney structures, and most have a second flue but only one cap like ours was originally.
If it's just a dummy flue absolutely remove it. I don't know why some masons did that. It's just stupid
 
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