Are there any good articles on chimney bracing?
We have a small ~24-30″ square masonry chimney that will be passing from the footing, through the first floor joists, through the rafter ties/loft floor joists, through the collar ties, and finally, through the roof.
At each point we see an opportunity for bracing the chimney, yet the code calls for 2″ separation from combustibles.
My question is, do we want to brace the chimney with the structure framing, and if so, what is the detail that allows for the connection? Is it some kind of flexible metal strapping?
Another consideration is the fact that the building will move and settle a little bit, and the chimney likely less so. If the bracing is too rigid and does not allow for movement, it could conceivably crack the masonry joints.
Any insights would be appreciated. Many thanks.
Replies
I've never seen a house with a brace to a masonry chimney. Plenty of chimneys are built to the top before the house is started and plenty of old chimneys are still standing 50 years after the house has fallen in. Bracing is not necessary unless you're in a seismic zone, are using metal flue or if your chimney extends far above ytour roof.
Agree with flo.
Rare to see but a standoff tied back to the roof when the chimney is high above the roof surface.
Follow this guide .
I should have added that this is a single flue chimney in a high-wind area...
The following article seems to suggest that this criteria would call for some kind of bracing, but again, it's a bit unclear...
https://www.finehomebuilding.com/2001/11/01/tying-a-chimney-to-a-house
Further, we are trying to keep the chimney on the smaller side, ideally two wythes thick with an ~9 -10" square opening to accept a 6" flue...
https://www.concreteconstruction.net/_view-object?id=00000154-254b-db06-a1fe-774b6d540000
The drawings are “shaded” and the script hard to see but there are sources listed you might be able to access.
The method I’m thinking of is using re-bar to reinforce the inside corners of your brick. Assuming solid brick. Run Re- bar vertically up the 4 inside corners. Tie with 1/4” wire wrapped around rebar and laid into the brick coarse horizontal joint.
How often tied to the brick? Every couple feet?
Look toward Long Island brick chimneys, they get some fierce winds.
Added:
https://www.concreteconstruction.net/how-to/reinforcing-new-and-old-masonry-chimneys_o
Calvin,
Thank you very much — this is what we were looking for. This strategy seems very smart for small footprint and single flue designs.
You owe me a beer.
I can travel.
Haha, absolutely!
Why do you want a masonry chimney?
What will you use it for?
The design and architectural character of the house calls for a masonry chimney.
It will be used to vent a wood stove.
Yes, I am aware that we can use stainless stove pipe and that it would be cheaper and easier.
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