With Allco having covered over 2,100,000m² of New Zealand in Volclay membrane over the last 17 years, Volclay can rightly be seen as one of New Zealand's most successful tanking products. Volclay product is applied to a wide range of projects, from small residential homes to large commercial builds. Allco are currently the waterproofing supplier for the Fonterra project on Fanshawe Street (which has included over 40 quality assurance inspections to date).
In the Britomart area, the Westpac Charter House was specified in the Volclay system, with completion in November 2008. With its location being so close to the water's edge, construction going lower than sea level and it having previously been a petrol station site, it showed Allco and Volclay's proven track record and quality within the New Zealand waterproofing arena.
The building of the three level basements required excavation down to 11m below street level and 8m below sea level, as well as the site being on reclaimed land. There was also ground contamination from its former use as a petrol station which was mitigated with the introduction of sediment control and filter pumping systems set up on site. Further pumping control issues were not helped by one of Auckland's wettest winters on record.
The Volclay Bentonite Waterproofing membrane and RX Waterstop were specified to fully encapsulate the three level carpark basement of Westpac Charter House.
The basement slab area was often under water with continual flow of water through the face of the sandstone wall. Volclay Voltex DS/SWR Bentonite membrane, which was specified for its ability to cope with contaminated and saline conditions, was laid beneath the floor slab and fixed directly to the sandstone walls. The walls were poured in-situ with RX Waterstop in all the cold pour construction joints.
On the vertical wall face at the sandstone and sheet pile junction and where the greatest water ingress was being experienced, Volclay Ultraseal SP was applied and overlapped with the Voltex (Ultraseal is compatible with Voltex).
Voltex and Ultraseal bond directly to the concrete through Volclay's advanced needle puncture technology. Volclay membranes allow for fast and accurate installation in wet and difficult site conditions.
Westpac Charter House project details:
Applicator: Sansom Construction Services Ltd
Builder: Hawkins Construction Ltd
Architect: Peddle Thorp
Project size: 5000m²
Products: Volclay Voltex DS/SWR, Volclay Ultraseal SP and Volclay RX101T Waterstop
Completed: November 2008
Warranty: Volclay full system warranty — 20 years
QA Visits: 45
Hydrostatic head of pressure: 11m