Selkirk
Background
Selkirk Brick started operations in 1883 and moved to the current Howitt
St site in 1900. This is approximately when continuous Hoffman-style kilns and chimneys were built. These became redundant after the construction of tunnel kilns in 1962. The 35m chimney of one of the kilns was retained because of its landmark presence and historical significance. No maintenance had been performed on the chimney in the 30 years since the crown had been removed and limited cementitious repair work had been undertaken.
Challenge
A survey and engineering report had established the chimney remained structurally sound but with gravitational hazards posed by concerning areas of loose and displaced masonry and significant deterioration of mortar joints. Spire was contracted to undertake rectification works
including full repointing, crack repair, reinstatement of loose brickwork
and replacement of the landmark signage.
Process
Through limited use of 45m EWPs, Spire was able to undertake initial
stabilisation and crack stitching reinforcement of the upper portion of
the chimney. Rope access lines were then rigged via a Spire-fabricated steel frame through the furnace door and over the chimney coping, thus avoiding tensile loads on the masonry. A natural hydraulic lime mortar
was formulated for compatibility with the porous original bricks. Stainless steel helical bar was grouted into bed joints to repair cracks. Signage was then measured, marked and removed, including the destructive fixings. Old mortar was then raked out and painstakingly repointed off ropes.
In places where brickwork was displaced, bricks were numbered and
removed before being relaid with fresh mortar. New signage was installed to complete the project.