Standing Tall: Conserving the Highett Gasworks Chimney
- computers67
- Aug 22
- 2 min read
The 27.5-metre-high former boiler house chimney (HO11) at Highett is the last surviving vestige of the 1938 Highett Gasworks. Stranded between the Nepean Highway and the Frankston railway line, the tall red-brick structure now stands alone.
The challenges of conserving a chimney like Highett’s echoes those faced by more famous masonry towers, such as those in Bologna. Like its Italian counterparts, it was not designed for longevity within a shifting urban landscape. The structural issues that plagued the medieval towers, their slender proportions, uneven settlement, and material fatigue, are mirrored here with similarly complex implications for conservation.
By the time conservation works commenced, the top three metres of the chimney, including its original corbelled cap, had already collapsed. As part of Development Victoria’s broader urban renewal of the precinct, RBA was engaged to lead a detailed program of structural remediation and heritage conservation. These complex works, carried out by Heritage Building Services, included the reconstruction of the missing rendered corbelled cap, widespread repairs to the brick masonry, and major structural interventions to ensure the chimney complies with current wind and earthquake performance standards. As RBA’s Senior Architect, Jeremy de Vos noted, ‘it was a project dense with structural puzzles and hidden surprises.’
Access required 35 metres of scaffolding, enabling a brick-by-brick approach to repair. The displaced bands were realigned, the missing crown rebuilt, and all original bricks carefully cleaned, catalogued, and reinstalled using lime-based mortars.
To ensure long-term structural stability, engineer Joe Spano designed a concealed post-tensioning system. Four steel rods were inserted within the chimney shaft, anchored to a cruciform steel frame at the top and tensioned at the base via a custom plate. This ingenious solution redistributed internal loads and enhanced the tower’s resistance to lateral movement without impacting its historic fabric - a stabilisation strategy not unlike those now used to secure leaning towers across Europe.
Unexpectedly, fifteen concrete ring beams were discovered hidden behind the face brickwork. The rings were an unusual, non-original intervention for chimneys of this kind. Likely introduced to manage stress, the rings had since deteriorated, with concrete cancer evident, causing cracking and bulging in the surrounding masonry.
In the lower section, the beams were removed and infilled with solid brickwork. The upper shaft was dismantled and rebuilt with new concrete rings placed at two-metre intervals. Salvaged curved bricks were reused wherever possible to retain the original character.
This successful conservation comes at a crucial moment. In Brunswick, the former Hoffman Brickworks chimney has stalled in a state of disrepair: scaffold has surrounded it since 2022, with Heritage Victoria issuing repeated repair orders and residents petitioning parliament amid safety concerns and rising costs. In comparison, Highett demonstrates how careful, committed heritage-led engineering and conservation can preserve heritage structures and facilitate urban renewal.
The restored Highett chimney now stands not just as a surviving industrial artefact, but as a carefully stabilised vertical structure adapted to survive within Melbourne’s growing suburban expanse. Like Bologna’s leaning towers, it is a reminder of how ambitious vertical forms often outlast their intended lifespans, and how their preservation demands a marriage of historical knowledge and engineering ingenuity.
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