Constructed in 1999, 633 Church St Richmond is a prominent eight-storey building that houses a restaurant on the ground floor and residential apartments from levels 2-8. The building features 84 reinforced concrete balconies which cantilever out on all sides of the building. Major problems identified by the owners included storm water penetration into the apartments and through the balcony slabs and severe corrosion to the steel balustrade support posts.

PROJECT HIGHLIGHTS

• Condition assessment, repair design/specification and project management of repairs
• 84 balconies and balustrades rehabilitated
• Rope access by Infracorr engineers for condition assessment
• Balcony waterproofing membrane failure, moisture entry into apartments and cracked balcony slabs
• Severe corrosion of steel balustrade support posts
• Major project to waterproof balconies and replace all glass balustrading to authority requirements

CHALLENGES

Access through the apartments was considered too intrusive to the residents. Hence, all works needed to be conducted from the building’s exterior. Water penetration into the apartments was occurring mainly via a construction joint between the balcony slab and the concrete ‘hob’ upon which the window is founded. The design needed to correct this issue. Water penetration into the apartments during the works was a potential risk. Hence it was imperative that the design provided minimum delays/cure between the work items. Corrosion of the existing balustrade support posts was largely occurring at or below the level of the tiles. The design needed to ensure this did not recur. Issues during the construction phase required Infracorr to:
• Liaise with local council to obtain the necessary permits.
• Ensure that the contractor’s works were performed in accordance with Infracorr ‘s specification.
• Project manage the works for the Owners Corporation

SOLUTION

Testing included balcony slab Half Cell Potential mapping and Ultrasonic Thickness Testing (UTT) to the steel balustrade posts. Infracorr performed the investigations utilising its IRATA trained rope access engineers. No structural problems were detected. The investigations enabled the preparation of a design for the rehabilitation works.
To ensure no recurrence of any water penetration, the design specified slab crack/joint sealing and two layers of cementitious membrane.
The initial membrane was required to be applied to the balcony slab and the second membrane to be applied to the new grading screed to be constructed over the initial membrane layer. Special requirements at the slab/window ‘hob’ and at all slab/wall joints were detailed.
Aluminium balustrading structural members were specified by Infracorr, with special waterproofing details required at the base of the posts.