Gallows Brackets to Support Chimney

In this blog, Icon Surveyors will be considering what a "Gallows Bracket" is and what it is used for?

What is a Gallows Bracket? What is It Used For?

In the simplest of terms,

A "Gallows Bracket" is steel support that is shaped at a right angle and used to support a chimney stack or breast when alterations to either are being carried out. These brackets, like their namesake, are extremely robust. As a chimney forms a part of the integral structure of a building, when a chimney is being repaired or removed, the remaining stack above and/or below it must remain steady. For this reason, "Gallows Brackets" are usually fitted at the party wall juncture of the stack.

There are certain regulatory and statutory matters that must be adhered to when removing and/or altering a shared chimney stack on a party wall. These include, but are not limited to, planning permission under the Town and Country Planning Act 1990, certain building regulations and the Party Wall ect. Act 1996.

However, permission from the planning department of the local council is not required if the proposed works are to remove an internal chimney breast (i.e., removal of the chimney below the roof line) or a chimney that does not form a part of a party structure. (i.e. a bungalow or house)

With regard to building regulations, these only apply if the proposed works are of a structural nature. Thus, as a chimney forms a part of the structure of a building and a "Gallows Bracket" is considered to be a new structure that supports the remaining overhead load of a chimney breast and stack, building control approval is required from the local council.

Regulations Pertaining to the Installation of a "Gallows Bracket"

  • The party wall to which the Gallows Bracket is to be affixed must be no less than 225mm thick.
  • The wall must be made of solid brickwork and it must be in a satisfactory condition (i.e., no serious cracks or bulges).
  • The width of the chimney breast can be no more than 1200mm. If wider, the appointment of a structural engineer is required.
  • The projecting chimney breast must not be any more than 340mm into the room.
  • The overhead chimney breast that is to be retained is not higher than two storeys (inclusive of roof space).
  • The brickwork above the line of the chimney cannot be more than that beneath it, otherwise, the wind may cause the stack to collapse.
  •  The minimal height of a ‘Gallows Bracket’ must be 1.5 times the projection of the chimney breast.

If any of the above stated building regulations, or indeed others that have not been mentioned, cannot be complied with, then another type of support mechanism, such as a structural steel beam (RSJ) may need to be used.

Anyone proposing to carry out chimney removal or alteration works should take note that building permissions are granted by local councils who have discretionary power to refuse to allow the use of 'Gallows Brackets' as a supporting mechanism for the structures of local buildings.

Icon Surveyors are happy to provide free party wall advice to any building or adjoining owners who may be affected by the subject matter raised in this blog.

Notice*: This blog is not an authoritative interpretation of the law; it is intended as a general guide.

Icon Surveyors

We are a team of party wall surveying experts based throughout London and the surrounding areas. Here, we share informative property survey blogs created by industry experts.