Chimney Corbeling: Chimney Masonry Repair

Hips and Shoulders: Chimney Corbeling

Chimney Corbeling can cause bigger problems so it is best to get the issue fixed sooner rather than later. The corbeling hips on your chimney could be allowing damaging water to come into your home. Corbeling aligns the shape of the smoke chamber to allow for better air flow inside the chimney. By design, the smoke chamber height can not be any bigger than inside width of the fireplace room opening, and the depth should not be greater than the depth of the smoke chamber.  The smoke chamber has to be placed at 45-degree angle and perched smooth on the inside.

Smoke Chambers

The shape of the smoke chamber should be capped off so not water can penetrate. Do it with concrete stones as you can see below. It is most important during construction any open voids of the brick itself are properly filled to prevent water penetration. Always remember small holes can allow gallons of damaging water in the chimney smoke chamber and even down into the firebox below. In the 60s 70s and 80s, many builders cut costs by making these flat instead of pitched at all. We’d always recommend having your chimney contractor take a picture of the top of the corbeling to determine if it needs a new stone cover, silicone waterproofing, or grind it out and tuck point it.

See also smoke chambers.
Here’s a perfect corbeling. Really doesn’t get better than this design!


This Chimney Corbeling looks fine from the ground up. But take note of the picture below…


Looking from the roof down you can see that poor masonry craftsman provided trouble for the homeowner. You need to fill these holes in the original construction.

Chimney Corbeling

Again looking down from the roof into the corbel, notice the large holes letting the water in and actually causing further damage. Shoddy craftsman has again failed these homeowners and created further damage.


Clay Lamb
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5 thoughts on “Chimney Corbeling: Chimney Masonry Repair

  1. What is the proper way to close off a flue that goes into a chimney still being used . Please help im not sure that it is being done properly by my contractor.

  2. Hello Ms.Eleanor, if it were mine I would have a Top Sealing damper installed at the top of the chimney. A top sealing damper is operated by a pull chain that is mounted in the firebox. Also, I think you’re gonna experience an energy saver by having this installed, there a number of models that a contractor can find, almost all of them work well. Stay warm and enjoy the holidays!

  3. Clay can you help me out. Im new to my house from 1978 and love burning fires all winter. I’m going to parge and smooth out my smoke chamber. How should I clean the smoke chamber so the mortar can stick better? Soap and a brush or some kind of cleaner? Also, how hard/long should I clean? Any advice would be greatly appreciated. Thanks

  4. Greetings Kevin,

    Honestly, I’ve never heard of this type of challenge which I compliment you that you’re even willing to consider it. Mixing soap and water with creosote sounds like a pretty awful mess that I don’t even to think about and as sidebar don’t want to even recommend. My recommendation would be to call in a chimney sweep to thoroughly clean it with a brush and then offer you up an estimate for repair with a product called ChimneySavers Chamber Coat. You may even find this product online. You may want to even contact the National Chimney Sweep Guild to find a chimney sweep in your area. There is a sweeps finder on If you had any questions about the product you can find that online as well. I compliment you, as gutsy as you are, are you looking for a part-time job? lol


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