Bracket chimneys:

This article explains what a bracket chimney is, why they are found (usually in older homes), why they are unsafe, and what to do about abandoning, removing or supporting a bracket chimney. We include photographs of bracket chimneys as well as sketches to help you recognize when this unsafe type of chimney is found in a building.

Bracket Chimney Collapse & Fire Risks

Definition of Bracket Chimney & Gallows Brackets

A bracket chimney is an incomplete masonry chimney, usually made of brick, that does not and perhaps never extended all the way down to a footing and foundation at ground level.

In North America we may find a bracket-supported chimney in an attic or on upper floors of an older home, usually pre-1900. It is possible that a bracket chimney.

[Click to enlarge any image]

In the U.K. and other countries the bracket that supports such a chimney is referred to as a gallows bracket, most-often supporting the upper portion of a chimney (chimney breast or chimney stack) when the lower segment has been removed during building renovations.

A gallows bracket is a right-angled structural support used to carry the weight of a partly-removed chimney, chimney breast, fireplace hearth, or the angled or non-vertical part of a masonry chimney.

As you will read here there are strict specifications for the dimensions, connections, and use of gallows brackets as unless these details are observed there are risks of dangerous chimney collapse as well as fire and potentially fatal CO (Carbon monoxide) poisoning from damaged or unsafe chimneys and flues.

Our photos above show two bracket chimneys in a pre-1900 home in New York. In our OPINION the supporting chimney bracket is unsafe.

Where you find a gallows bracket under a chimney like the one in our photo, it's likely that that chimney originally extended to ground level but its base has now been removed.

A wooden framed "bracket" supports a masonry chimney on and in a building. Current building codes which require that a masonry chimney be self supporting expect that a masonry chimney will rest on a footing below ground level where it is sound and protected from frost, settlement, tipping, movement.

Wood bracket supports for masonry chimneys such as shown in our sketch (left) are often under-designed and lack sufficient strength to carry the weight of the chimney over time. Further, wood chimney supports may decay from leaks, rot, and insects.

As Carson Dunlop point out in this sketch, these chimneys are often inadequately supported and are a collapse hazard.

If the bracket-supported chimney is in use there are very often fire hazards as well.

Inspectors of older homes may find a bracket chimney in the building attic, with no masonry extending to the floors below. Instead, a wood stove or coal stove on lower floors used a metal chimney which passed up through the ceiling above and into the bracket chimney supported on a wood shelf in the attic. From outside the building it may appear that a normal masonry chimney is installed - possibly a false and unsafe assumption.

Watch out: bracket chimneys or chimney remains supported by a gallows bracket may be unsafe, risking structural damage or even collapse. Because considerable weight of the remaining chimney masonry may be involved the supporting gallows bracket must be of sufficient strength.

Watch out: as we note below, (Richmond, U.K.) Gallows Bracket chimney supports are not permitted and would be unsafe if installed in lime-mortar masonry walls.

On a home where we find a timber gallows bracket the risk of a building fire (if the chimney remains in use) leaks, rot, failure of structural connectors, failure of the supporting brick or masonry wall all add to the risk of a collapse that would damage the building and may harm building occupants.

Fireplace Hearth Support Brackets or chimney breast supports are also referred to in some countries as a gallows bracket.

See details

at FIREPLACE HEARTH DIMENSIONS & SUPPORT

 

Repair alternatives for bracket chimneys & gallows brackets

Options for repair or replacement of bracket or partly-abandoned chimneys or supporting chimney brackets or gallows brackets include:

• Abandonment and removal of the chimney it its use is not necessary
• Removal of the bracket chimney and replacement with a listed metal chimney which will almost certainly be of much lighter weight as well as meeting modern fire clearance and safety requirements.
• Inspection, approval, or repair / additional support for the chimney bracket / gallows bracket and the wall that carries the bracket and thus also the weight of the chimney.
• Where a gallows bracket or chimney bracket is not safe or not permitted in support of a chimney or fireplace breast / hearth for any of the reasons cited in this article, it may be possible to provide adequate support using a combination of steel support beam and supporting posts.

Bracket Chimney & Gallows Bracket Safety Research

Sketch: illustration of typical gallows bracket chimney or chimney breast support, adapted from Richmond U.K., cited below. [Click to enlarge any image]

• El Shenawi-Ali, Karim, "A Guide to Gallows Brackets: How it Supports to Chimney Breast or Stack", Berry Lodge Chartered Surveyors, 61 Highgate High Street, (Upper Floors) London, N6 5JY U.K. Tel: 020 7935 2502 Email: info@blsurveyors.com 2017/10/16 - retrieved 2021/06/05 original source: https://www.blsurveyors.com/a-guide-to-gallows-brackets/
  
  Excerpt:
  
  Gallows Brackets [were] used [in the U.K.] from the 1800s up until present day as a mechanism to support numerous structures, and get their name from the shape of the structure historically used in hanging, ie the gallows!
  
  
• El Shenawi-Ali, Karim, "What are Gallows Brackets"? 2017/07/04 Op. Cit.
• Friend & Falke," RICS Valuer Inside Knowledge – About Gallows Brackets" Friend & Falcke, Chartered Surveyors, RICS [Royal Institute of Chartered Surveryors], temporary location is The Pavilion Business Centre, 96 Kensington High Street, London W8 4SG U.K., Web: http://friendandfalckesurveyors.co.uk/ Email: professional@friendandfalckesurveyors.co.uk Tel: +44 (0)20 3355 7909 retrieved 2021/06/05 original source: http://friendandfalckesurveyors.co.uk/rics-valuer-inside-knowledge-about-gallows-brackets/
• LABC, HOW TO GET IT RIGHT: REMOVING A CHIMNEY THE RIGHT WAY [PDF] LABC News, 2018/09/21 retrieved 2021/06/05 original source: https://www.labc.co.uk/news/how-to-get-it-right-removing-chimney-right-way-video-showing-wrong-way
  
  Watch out: do not use any of the following to support a chimney or chimney breast or gallows bracket:
  
  Excerpt:
  
  Corbelled Brickwork – into existing brickwork should not be attempted as it will not be possible to gain a sufficiently strong bond between the new and existing brickwork.
  
  [See hearth drawing below for an example of corbelled brickwork supporting the hearthstone.]
  
  Timber bearers onto the existing floor or ceiling joists – as the point load passed onto the floor or ceiling timbers will be significant and may lead to collapse.

Above: fireplace parts illustrates brick corbelling supporting the hearthstone.

Illustration: 375 x 375 mm Gallows Bracket from Teco, U.K. cited below.

• Teco, GALLOWS BRACKET SUPPORT for INTERNAL CHIMNEY BREAST REMOVAL [PDF] TECO Building Products, Wellington Road, Portslade, Brighton, East Sussex, BN41 1DN U.K., Tel: 01273 423 983 Emal: sales@tecoproducts.co.uk TECO Building Products, Wellington Road, Portslade, Brighton, East Sussex, BN41 1DN retrieved 2021/06/05 original source: https://tecoproducts.co.uk/products/miscellaneous/gallows-bracket/
  
• Richmond, U.K., CHIMNEY STACK REMOVAL AND THE BUILDING REGULATIONS [PDF] London Borough of Richmond Upon Thames, Civic Centre, 44 York Street, Twickenham, TW1 3BZ U.K., retroved 2021/06/05 original source: https://www.richmond.gov.uk/chimney_stack_removal_and_the_building_regulations
  
  Excerpt:
  Use of gallows brackets
  
  Where the chimney breast does not protrude from the wall by more than about a third of the thickness of the wall, the brickwork may in some circumstances be corbelled out or have gallows brackets installed.
  
  Watch out: Where lime mortar has been used or the neighbour’s flues are in line with yours the use of gallows brackets would not be acceptable.
• Weeley TDCBCS, REMOVING A CHIMNEY - Gallows Bracket Specifications [PDF] Tendring District Council Building Control Service Weeley, Tendring Building Control Town Hall Station Road Clacton-on-Sea Essex, CO15 1SE UK Tel: 01255 686111 retrieved 2021/06/05 original source: https://www.tendringdc.gov.uk/sites/default/files/documents/planning/building%20control/Removing%20a%20Chimney.pdf
  Excerpts:
  
  CAN THE CHIMNEY BE REMOVED?
  
  If you want to remove a chimney breast in a ground or first floor room you must first support the remaining chimney adequately. A structural engineer should be contacted to give advice on the correct design for your building. It is not satisfactory to corbel the brickwork below the remaining chimney stack. It must be properly supported at all times.
  
  SUPPORT
  
  The preferred method of supporting a stack is to use a steel beam supported on suitable load bearing walls. Where this is not possible an alternative method of support may be by the use of brackets, commonly referred to as gallows brackets. There are restrictions which apply to the use of gallows brackets and these are detailed below.
  
  Steel beams should be designed by a structural engineer. A structural engineer should always be consulted regardless of the support method where large stacks are being removed. Timber beams and corbelled brickwork are not considered satisfactory in any circumstances.
  
  Where hearths and breasts are being removed it is often necessary to insert replacement floor/ceiling joists. It is essential that they are of an adequate size.
  
  UNDER WHAT CIRCUMSTANCES MIGHT GALLOWS BRACKETS BE AN ACCEPTABLE METHOD OF SUPPORT?
  
  Gallows brackets are only suitable in certain situations. It is recommended that they are not to be used if the brickwork to which they will be attached is bonded together with lime mortar. The brickwork and the mortar joints will also need to be in a very good condition if gallows brackets are to be used, i.e. not dry and crumbly.
  
  Gallows brackets should only be used on walls that are a minimum of 225mm thick. The projection of the breast should be no more than 340mm. The stack itself should not be completely vertical (i.e. a gathered flue to a central stack).
  
  This is to allow some of the loads to be supported by the remaining parts of the chimney. The chimney is in a house of no more than two storeys.
  
  If the neighbouring property has had their adjacent chimney breast removed previously, or partially removed and gallows brackets used, then gallows brackets will not be acceptable for removal of the chimney breast. A steel beam support will then be required.
• Wikipedia, "[Definition of] Chimney Breast", retrieved 2021/06/05 original source: https://en.wikipedia.org/wiki/Chimney_breast
  
  Excerpts:
  
  A chimney breast is a portion of a chimney which projects forward from a wall to accommodate a fireplace. Typically on the ground floor of a structure, the masonry extends upwards, containing a flue which carries smoke out of the building through a chimney stack.
  
  Chimney jambs similarly project from the wall, but they do so on either side of the fireplace and serve to support the chimney breast. The interior of a chimney breast is commonly filled with brickwork or concrete.
  
  Chimney breasts often become redundant with respect to their function as a chimney, due to installation of alternative heating methods such as central heating. Removal of the chimney breast can provide more floor space and a more regular shaped room.
  
  Watch out: However, chimney breasts often have structural function. Therefore removal needs to be done with care, and preferably with professional advice.
  
  The removal of part (especially the lower part) of a breast can cause uneven loading on a wall, especially if the upper part is not suitably supported, ideally on an I-beam.[6] In some cases support on a steel beam and post, or by gallows brackets may be acceptable.
  

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Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

Question: identify this H. Waudby Patent 1870 cement / plaster house or chimney part

Do you know what this is? We can see it in the neighbours house through the joist space of the first floor (ceiling of the main level). Perhaps could have attached to a bracket chimney on the second level.

It is not where the current washroom is, not where you would imagine a washroom ever was.

Nothing comes up when I google “H. WAUDBY’S PATENT 1870”. - Anonymous by private email 2021/05/04

Coal chute? Garbage chute? [original source: https://forgottengalicia.com/wp-content/uploads/2013/01/majestic-coal-chute.png ]

Moderator reply:

No, though knowing the location and age of the building where this detail was found would be helpful

If you agree I'll find a place to post the photo and invite comments from readers - someone may recognize this in-wall details.

Our default is to keep you anonymous unless you ask otherwise

More photos of more details would be useful

There was a Canadian inventor of that name.

• No. 585— WAUDBY, (H.,) of the Village of Thornhill, in the County of York, for a " New Centre Force and Suction Pump." Toronto, dated 17th January, 1856. Canadian patent

Is the home where this Waudby patented item is found located in Canada?

Reader follow-up:

Yes, please feel free to post. Unfortunately don't have any more photos.
The building is a row house in Toronto, ON, Canada, built in (I think) 1888. Wood frame, you can see the plaster and lath ceiling in the photo.

There is a bracket chimney on the second level at approximately this location.
Yes, I found that too about the suction pump by Waudby, but can't find anything more.

Moderator reply:

Done; we'll see if other readers can identify the 1870 Waudby patent device shown in your photo.

More details about exactly were this is located in the home and observations around that cut-out in the plaster-lath ceiling (?) at the same location would be diagnostic.

My working guess is that Waudby patented a fire-resistant chimney thimble that allowed a woodstove to be connected to a bracket chimney in your Toronto home.

If that masonry device by H. Waudby and patented in 1870 were part of a coal chute you'd be able to find a potential route down through a wall into a basement coal bin - not likely to be in an interior ceiling; and you'd find some black dust or marks nearby where coal passed. If you get more photos and if you can add more details about the history of your home, photos of the home from outside and of its chimneys and roof including where old chimneys may have exited that would be most helpful. 

I've tried genecology research for the Waudby name to identify Canadians born in the earlier 1800s but with no obvious match.

Question: are bracket chimneys approved?

(Apr 12, 2016) Anonymous said:

are bracket chimneys approved for venting per washington codes

This Q&A were posted originally

at BRACING for METAL CHIMNEYS

Reply:

Anon:

The model building codes such as ICC's chapter 10 (that's what's cited and copied in Seattle's 2012 residential chimney code) don't mention the term "bracket chimney"

But that is a common term to describe a chimney like the one in our photo and that's discussed in detail in the article above on this page.

I am not a code official: your local building code official's word is law where you live. However I can give my lay OPINION that bracket chimneys ought to be prohibited for safety reasons, and I note that the model codes include a paragraph about chimney supports relying on a footing. For example

R1003.2 Footings and foundations. Footings for masonry chimneys shall be constructed of concrete or solid masonry at least 12 inches (305mm) thick and shall extend at least 6 inches (152mm) beyond the face of the foundation or support wall on all sides. Footings shall be founded on natural undisturbed earth or engineered fill below frost depth. In areas not subjected to freezing, footings shall be at least 12 inches (305mm) below finished grade.

The requirement for a footing and foundation supporting a masonry chimney would exclude bracket chimneys in new construction.

Question: minimum footing size for a bracket chimney installed on ground floor center of a structure or over a main beam

(Aug 19, 2014) brandon whitney said:

what would the typical minimum footing size be for a bracket chimney or any chimney installed on a ground floor center of structure on main carrying beam located in basement under first floor floor joist? hope this question makes sense we should have been lawyers lol

Reply:

Brandon
Take a look at the page top photo: a bracket chimney has no footing and is supported by building framing. This is not a modern construction.

The footing size for "any chimney" is a bit of a broad question since chimney materials vary significantly in support requirements. Metal chimneys are typically supported by connections to the structure.

Masonry chimney footing requirements depend on soil properties and chimney materials and size and thus weight. So I'm chicken to give a simplistic single answer.

Here is a quote from Chapter 10 of the ICC model code

R1001.2 Footings and foundations. Footings for masonry fireplaces and their chimneys shall be constructed of concrete or solid masonry at least 12 inches (305 mm) thick and shall extend at least 6 inches (152 mm) beyond the face of the fireplace or foundation wall on all sides.

Footings shall be founded on natural, undisturbed earth or engineered fill below frost depth. In areas not subjected to freezing, footings shall be at least 12 inches (305 mm) below finished grade.

On 2018-12-15 by Anonymous

looking for information on Chimney Brick ties

On 2016-10-15 by Jim

Sorry to be a bother. Same chimney, noted before. ....i understand the footing specs. I am on first floor, so easy enough

Does it need to be reinforced by rebar? Secondly, does the material from the footing up have to be masonry, or can steel bars or wooden 4'x4"s be used, one on each corner of the existing bracket chimney to the footing.

I could then frame them in and cover them with wainscotting to match the kitchen. Is this an option?

On 2016-10-15 by Jim

I recently discover a bracket chimney in my kitchen that had been covered up. I would love to use it for a small wood stove. The current supportis nothung but a pallet secured to the wall studs. How it stays up amazes me.

How might i repair and add additional support to this chimney?

...

Continue reading at CHIMNEY COLLAPSE RISKS, REPAIRS or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see thee

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• BRACING for MASONRY CHIMNEYS
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