Can’t We Use Gallows Brackets for Chimney Support?

If you are removing a chimney breast from the ground floor or first floor but retaining it above, you need something to support the remaining chimney stack. Gallows brackets are sometimes suggested for this purpose. PorthouseDean does not recommend them, and in most cases will not calculate for them.

What Are Gallows Brackets?

Gallows brackets are cantilevered metal brackets bolted into the masonry wall at the sides of where the chimney breast has been removed. They project inward to support the underside of the continuing chimney above. The idea is that the brackets transfer the chimney’s weight into the flanking walls.

Why We Don’t Recommend Them

There are several well-documented problems with gallows bracket installations:

Brickwork condition. The masonry around a chimney breast removal is often in poor condition — fire damage, repeated thermal cycling and age all degrade the mortar and brick. Gallows brackets rely entirely on the quality of that masonry for their fixings. Weak masonry means inadequate fixing capacity, which means inadequate support.

Recorded failures. Gallows bracket failures have been documented on projects across the country, resulting in partial chimney collapse. This is a significant health and safety risk, particularly if the property is later sold and the new owners are unaware of the arrangement.

Building Control scrutiny. Many Building Control Officers now refuse to accept gallows brackets as a sole means of support for a chimney breast, particularly in older properties. The LABC has also tightened guidance in this area. Submitting a design relying on gallows brackets may lead to rejection and delays.

Party wall risk. Where the chimney breast is on or near a party wall, any movement caused by inadequate support can cause damage to the neighbouring property — triggering a party wall dispute.

What Should Be Done Instead?

The safe and reliable alternative is a steel beam. A beam spanning across the opening in the flanking walls provides positive, calculable support for the chimney above. The beam is sized by a structural engineer, padstones are specified to spread the load, and the result is a design that Building Control can approve with confidence.

This approach is structurally sound, buildable and fully documented in a calculation pack. It costs more than gallows brackets, but the risk difference is substantial.

Working With PorthouseDean

PorthouseDean designs steel beam solutions for chimney breast removals across the UK. If you have been advised that gallows brackets will work, we recommend getting a second opinion. Get in touch to discuss your project.