MJ Engineering Projects supervised remedial works on a twenty-two-level commercial tower on Pitt Street. The precast-panel, beam-framed structure showed widespread concrete spalling caused by low cover and carbonation, together with perished sealant at movement joints. The client required a programme that would restore façade durability, protect reinforcement and keep office operations running without major disturbance.
Project background
Initial inspections confirmed concrete cancer at multiple panel junctions where reinforcement had insufficient cover. Laboratory tests showed carbonation depths reaching the steel, and sealant beads around vertical and horizontal joints were cracked, letting moisture enter the concrete matrix. MJ Engineering Projects prepared a remedial works specification that aligns with current National Construction Code clauses and prescribes compatible repair materials. After a selective tender a specialist contractor was appointed, and our team acted as superintendent to certify quality, track budget and coordinate works during regular business hours.
Scope of works
- Repair concrete spalling on façade panels
- Remove and replace deteriorated joint sealant
- Apply polymer-modified render across repaired areas
- Coat the rendered façade with high-performance acrylic paint
Key challenges and solutions
Concrete spalling at height
Spalls appeared across several storeys, requiring safe high-access methods. Suspended swinging stages were installed in zones to keep footpaths open. Technicians broke out unsound concrete, cleaned and passivated reinforcement, then reinstated cover with polymer-modified mortar. Feathered edges blended patches into adjacent panels before rendering.
Joint sealant deterioration
Aged sealant around movement joints had cracked and lost adhesion. Crews raked out the old material, primed the concrete arrises and installed a suitable joint sealant resistant to ultraviolet exposure. New beads restore weather tightness and allow thermal movement without tearing.
Uniform façade finish
After patch repairs the façade showed colour variations between original panels and new mortar. A thin polymer render supplied by the contractor provided a continuous surface, followed by two coats of high-performance acrylic paint specified in the project documents. The system delivers carbonation resistance and a consistent appearance suited to the busy Pitt Street context.
Office occupancy and scheduling
The tower remained fully tenanted. Noisy chipping and grinding were confined to 6.00 am-9.00 am; quieter tasks such as sealant tooling and painting followed through the day. Lift lobbies stayed clear by staging material hoists before 8.00 am, and protective screens shielded glazing from accidental impact.
Conclusion
The Pitt Street remedial works programme eliminated concrete cancer, reinstated joint integrity and provided a durable, visually uniform façade without disrupting daily business activity. Concrete repairs are fully protected by render and high-performance acrylic coating, movement joints are resealed and the tower’s external envelope now meets contemporary durability expectations.
MJ Engineering Projects combines more than twenty-five years of remedial works experience with careful project supervision to keep Sydney’s commercial buildings safe and attractive. For further case studies visit our blog or contact the remedial works team for guidance on façade repairs, concrete cancer treatment and joint renewal.
