Christchurch Town Hall

Early in 2019 the Christchurch Town Hall for the Performing Arts re-opened its doors after an eight-year hiatus following the February 2011 earthquake.
BY JENNY BAIN for RoofLink, RANZ's quarterly roofing industry members' magazine - see information here

Cantabrians regard its town hall as a civic treasure. Opened in 1972, it has served as the region’s premium venue for art performances for almost 40 years. However, following the 2011 earthquake, it suffered substantial damage and the complex was forced to close – primarily due to liquefaction of the ground beneath spreading laterally towards the nearby River Avon. It was only during its major reconstruction, which began in 2015, that a full, post-tremor inspection of the roof could be made, which revealed the original Butynol® membrane had survived the earthquakes remarkably well. The roof was still in good condition. However, the scale of the reconstruction meant structural strengthening would involve cutting into the roof, which would have compromised the existing membrane, so it was decided to replace it.

Renamed in 2007 the Christchurch Town Hall of the Performing Arts, initial thoughts following the earthquake were that all but the auditorium of the town hall should be demolished. But, in 2012 councillors voted to rebuild, maintaining its original features, with improvements made to some parts of the complex. The design follows the central vision of architects Warren and Mahoney, who along with Hawkins Construction brought the reconstruction project to its conclusion – Warren and Mahoney having designed the original town hall.

The extent of damage to the town hall following the 2011 earthquakes meant the structural challenges were epic: The foundations were replaced with concrete columns, each six to eight metres in length, sunk into the ground to support and stabilise the building. The original concrete slabs were removed and replaced with new ones. In total 30,000 cubic metres of concrete was poured into the refurbished building with design improvements made in many areas of the building, including the James Hay Theatre, which was modernised and a restaurant and function rooms built anew.

RANZ member JPS Roofing Ltd was engaged for the roofing aspects of the redevelopment. The company was established 30 years ago and is owned and operated in Christchurch with director Jason Savage at the helm. The firm has been involved in other premier projects in the city, including the Christchurch International Airport (another Hawkins development), the Farmers
Northlands re-roof (4,000m2 membrane), the Latimer Hotel, and the grandstand at the Hagley Oval.

Savage says although the original roof was still performing well, it was to be replaced with 1.5 DG Butynol®, noted for its longevity, appearance and reduced heat draw, and to be in keeping with the heritage status of the building. In the 48 years since the town hall was first completed, nothing too much has changed with the product selected, he says.

The re-constructed Town Hall has been the longest and largest job to date for JPS Roofing – 2016 to 2020, covering 6,000sqm over three years. Its complexity contributed to a plethora of design changes, but also the scale of the build meant Savage often found himself dealing with not only architects, the main contractor, the project manager, and four builders from Hawkins, but also frequently different workers on site from Trade Assist. There were also occasions when specified details needed JPS’ involvement and explanation to come up with the best way to achieve them. Sometimes these details required hours and hours of work.

For the re-roof to begin, existing plywood was removed and new plywood installed across the majority of the building. First up, Savage noted that a carbon fibre, concretestrengthening material had been wrapped on the auditorium roof (this prep work having been performed by another company). JPS needed to test extensively to ensure compatibility with the glue for the membrane to be laid on top of this carbon fibre material. Thus, began the lengthy process of systematically stripping away the old membrane; a team of six installers from JPS working on removal and replacement over the whole town hall complex, including the modernised James Hay Theatre, kitchen, new restaurant and function rooms. The oval roof of the auditorium, which is shaped like a sail, provided some difficult angles, as did the design of the re-vamped theatre.

Persistent and ever changing wind directions were a constant issue during this phase of the JPS contract, says Savage. Savage also mentions constant design changes over the course of the project, including provision for plant that was omitted from the original plan and added at a later date, along with falls and gutters, retrofit skylights and numerous vents and harness points – to name a few. Given the historic nature of the building – it is a Category 1 listed building under the Historic Places Act – its revival has embraced its past, but has emerged from the horror of its demise in 2011 with updated features in line with current standards.

Forty-eight years after it was first opened, the Christchurch Town Hall of the Performing Arts has again become the ‘living room of the city’; a cultural centre for concerts, graduation ceremonies and many other events and shows for Cantabrians, who waited eight long years, to reclaim their treasured city icon.

Savage is justifiably proud of completing this contract on a building of such importance to the people of Christchurch, with a structural refurbishment that respects the building’s heritage values. Every job has its frustrations and this contract had many, he says, but JPS Roofing has now completed its longest duration re-roof and for him and his team it’s been a privilege to be involved in bringing the town hall back to life. His favourite part of the reconstructed town hall is the new addition of a practise room for the Christchurch Symphony Orchestra, which he thinks, is awesome.