Image courtesy of Win Clark. Disclaimer: Images are for illustrative purposes only. We do not assert that any building shown or part thereof is earthquake-prone. Further we do not guarantee that any building, part thereof or associated work will be eligible for the Heritage EQUIP fund. Information on eligibility is available at Am I eligible.


Parts of brick masonry chimney stack break off or entire chimney stack collapses into roof, ceiling space or onto ground.

Potential structural strengthening projects

a)     A galvanised steel tube is fitted into the chimney flue and grouted in place.

b)     Stainless steel Helifix bars form a series of hoops around the perimeter of the chimney-stack by mortaring into selected horizontal joints of the brickwork.

c)     Within a ceiling space, a structural frame is made from steel angle sections and installed to fit snugly around the four sides of the stack. The four sides of the frame are fixed together by bolting at the corner junctions. Proprietary steel strap bracing can be fitted to the ceiling or roof framing where the loading from the chimney stack is to be transferred to bracing walls.

d)     Where a chimney stack may fall away from the building, it can be tied back into the building at the level of floor or roof structure (diaphragm). The tie at each level is formed from a galvanized flat steel bar that is formed into a two-piece frame (yoke), with each piece fitted and fixed around the chimney-stack, through the wall and twisted flat to be fixed to the floor framing under the plywood structure (diaphragm).

Possible first steps with a structural engineer

They assess the structural capacity of the chimney stack and provide specifications for required strengthening work.

Updated on 15th December 2016