Gallows Bracket Calculations

Over the last few weeks, beamcalc.co.uk has had a large number of enquiries regarding the removal of chimney breasts and supporting the remaining chimney breast and chimney stack in and above the roof space with gallows brackets. This work is controllable building work and would require Building Regulation approval. The easiest and quickest way to notify the Local Authority would be by submitting a Building Notice.

​The LABC has published some very useful guidance with regard to the removal of chimney breasts and the use of Gallows brackets, (available here) . There are a number of criteria that must be met in order to use a Gallows bracket solution. If any one of these criteria can’t be met then the support must be designed and justified to the Local Authority by calculation. The usual method is the insertion of steel beams and/or steel posts into the property.
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To summarise the LABC guidance – Gallows Brackets CAN’T BE USED if you answer YES to any of the below – If you are unsure and need to discuss your proposal or you would like a fee quote for an alternative solution please contact beamcalc.co.uk for assistance. 

LABC GALLOWS BRACKET CHECKLIST
Are the bricks laid in lime mortar?
Is the brickwork in poor condition?
Is the supporting wall less than 225mm thick?
Does the chimney stack project more than 340mm?
Is the stack only partially bonded to the supporting wall?
Has the neighbour’s part of the stack already been removed?
Will there be more brickwork left above the roof than below?
Is the house more than two storeys high?
Is the stack vertical without loads being shared?
Does the stack buttress the supporting wall?