MJ Engineering Projects supervised remedial works on one of the key academic buildings at the University of New South Wales (UNSW) Kensington campus. The concrete-framed structure features sandstone fin walls and serves heavy pedestrian traffic during semesters. Defects included severe concrete spalling, asbestos-laden joints and water-affected sandstone. The university requested a programme that would restore safety and appearance while keeping daily operations and student movement largely unaffected.
Project background
Investigation revealed that carbonation and chloride ingress had reduced concrete cover, causing steel reinforcement to corrode and spall. Asbestos putty within the sandstone fin-wall joints posed a health risk, and water infiltration had stained and weakened external stonework. MJ Engineering Projects prepared a remedial works specification consistent with National Construction Code requirements, then managed a select tender to appoint a specialist contractor. Because lectures continued during construction, noisy tasks were restricted to 5.00 am – 9.00 am, with all works finishing each day by 2.30 pm. Safe pedestrian detours and clear signage ensured uninterrupted campus access.
Scope of works
- Strip asbestos putty from sandstone fin-wall joints
- Repair extensive concrete spalling with high-performance repair mortars
- Insert pins and window brackets to support cantilevered concrete sections
- Fabricate and install project-specific formwork matching slab length, angle and pitch
- Apply waterproof membranes and sealants to sandstone fin walls
Key challenges and solutions
Working hours and campus access
Classes and foot traffic remained high throughout the semester, so the remedial works team adopted an early-start schedule. Noisy hammering and grinding finished by 9.00 am, after which low-impact tasks continued until 2.30 pm. Pedestrian routes were protected with overhead gantries, and marshals directed students during material deliveries.
Asbestos removal next to active classrooms
Removing asbestos putty required strict safety measures. Negative-pressure enclosures were erected around each joint location, and air monitoring ran continuously. Clearance certificates were issued before adjacent rooms reopened, maintaining compliance with SafeWork NSW procedures.
Concrete spalling on cantilevered elements
Spalling occurred along projecting slab edges. Custom formwork was built to match the varying slab pitch, allowing precise placement of repair mortar. Stainless pins and window brackets were installed to strengthen the cantilevers without altering the building’s heritage-listed profile.
Cathodic protection integration
To halt further corrosion, an impressed-current cathodic protection system was installed on affected concrete panels. Cabling and anode locations were coordinated with the new repair zones, providing long-term defence against concrete cancer.
Waterproofing sandstone fin walls
After repairs, membranes and breathable sealants were applied to the sandstone fins. The products selected preserved vapour permeability while preventing future moisture ingress, satisfying heritage guidelines endorsed by the university’s consultants.
Conclusion
The UNSW Kensington remedial works programme addressed concrete cancer, asbestos hazards and water ingress while respecting strict time and access constraints. Sandstone fin walls are now watertight, concrete elements are reinforced and protected by cathodic systems, and asbestos putty has been safely removed. These outcomes were achieved without disrupting lectures or pedestrian flow, demonstrating MJ Engineering Projects’ capacity to deliver complex remedial works in sensitive, high-use environments.
For additional remedial works case studies, visit our blog or contact the remedial works team for guidance on concrete repair, waterproofing and heritage façade maintenance.
