# Best chimney crown? Limestone/concrete vs. all concrete



## Studly (Feb 27, 2009)

We are getting estimates on having a proper chimney crown built to prevent the brick spalling that has occured on our chimney. Our current crown is made of mortar and has cracked and doesn't overhang the bricks.

Most contractors who have given us an estimate will build the crown out of pure concrete with an overhang, but one company that specializes in chimney repair builds the crown using a limestone slab and puts concrete on top. The limestone looks very nice and they say performance will be similar to an all-concrete crown, and they give a 10 year warranty against cracking.
Which would you choose and why?


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## Dave Sal (Dec 20, 2012)

I had that problem about 15 years ago. Ended up removing the cracked mortar and replacing it with a precast crown. Works great and completely solved the issue. Unfortunately I don't have any pics or even remember how much it cost but it wasn't very expensive. It did weigh quite a bit though and getting it up the ladder was a bit rough.


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## Studly (Feb 27, 2009)

Dave Sal said:


> I had that problem about 15 years ago. Ended up removing the cracked mortar and replacing it with a precast crown. Works great and completely solved the issue. Unfortunately I don't have any pics or even remember how much it cost but it wasn't very expensive. It did weigh quite a bit though and getting it up the ladder was a bit rough.



Good to know ... thanks. I assume that is precast concrete? Is it still uncracked and in good shape?


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## ClarenceBauer (Mar 4, 2005)

I have worked on many Historical structures that had different type chimney caps. The oldest & the ones that lasted were made of ONE solid block of Limestone. All the brick caps that were covered with Stucco had failed & most if not all which had concrete caps had problems & or bad cracking. My question is if it is a one piece slab WHY the cement topping. Concrete is not compatible over Sandstone & Limestone the concrete is very hard compared to the stone.


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## Gregsoldtruck79 (Dec 21, 2017)

No one except me like the Stainless Steel crowns ? Maintenance free and done. Although some lightning protection may be in order for it. 

(Not for historically accurate homes through)


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## Studly (Feb 27, 2009)

ClarenceBauer said:


> I have worked on many Historical structures that had different type chimney caps. The oldest & the ones that lasted were made of ONE solid block of Limestone. All the brick caps that were covered with Stucco had failed & most if not all which had concrete caps had problems & or bad cracking. My question is if it is a one piece slab WHY the cement topping. Concrete is not compatible over Sandstone & Limestone the concrete is very hard compared to the stone.



I assume the concrete on top of the limestone slab is to add a slope so water drains off of it, and adds strength. Good to know your experience with old chimneys with a limestone crown!


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## ClarenceBauer (Mar 4, 2005)

Studly said:


> I assume the concrete on top of the limestone slab is to add a slope so water drains off of it, and adds strength. Good to know your experience with old chimneys with a limestone crown!


If he can't slope the natural stone for drainage then he should use a mortar that is designed for Brownstone , Limestone & Sandstone.
Cement over time will delaminate from the stone.


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## Studly (Feb 27, 2009)

Here's a photo of a limestone/concrete chimney crown that is very similar to what the one contractor is proposing.


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## chandler48 (Jun 5, 2017)

I'll side with you Greg, but no one is listening. Stainless with a perimeter kick out is the way to go.


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## Dave Sal (Dec 20, 2012)

Studly said:


> Good to know ... thanks. I assume that is precast concrete? Is it still uncracked and in good shape?



Yes it is. I'd climb up on the roof and take a pic but its about 90 degrees outside now. :biggrin2:


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