Christchurch legacy at risk as city crumbles

As Christchurch continues to be shaken, heritage experts face some tough decisions.

Early December 2011. Ken Franklin has just made a decision. No more propping or temporary fixes to the Christchurch Arts Centre.

Given the cluster of historical buildings' precarious state, it's either a terrible gamble or a brave vote of confidence in the future. Possibly both. Unlike many landmark heritage buildings, the Arts Centre has survived Canterbury's devastating earthquake swarm and is still standing. Just.

When we speak again, it's a few days after Christmas.

"There is an awful sense of dread. They just come out of nowhere. You never know when it's going to happen next," says Franklin, the Arts Centre director, of the latest quakes that hit on December 23. "We had quite a bit more stone lost from upper levels, especially gables on Worcester Boulevard, but nothing major. We seem to have hung in there. The buildings are still standing. They have shown remarkable resilience to date."

Famous people were here - Ernest, Lord Rutherford, Sir Apirana Ngata and Dame Ngaio Marsh among them. History seeps from these stones, but then you see the present - crack lines, split archways, wrenched piers, walls rent asunder.To walk through this complex of gothic stone masonry buildings dating back to 1877, as I did in early December, is to tread the halls, cloisters and quadrangles of what was Canterbury University College and two former secondary schools.

"If we do get a shake, stick with me," says Franklin. "Running outside isn't always the right thing to do here." The destructive impact of huge stones crashed down from gable tops indicates what he's talking about. When the circular Observatory tower collapsed in February two contractors were working inside. They followed the safety advice given and moved to the street side of the building. Their car beside the tower was crushed.

The buildings are a patchwork of "make safe" mechanisms: posts under archways, crucially installed in September 2010 and preventing further damage; extensive steel propping against the Clock Tower; a 20-tonne turret on the footpath beside the Great Hall which was fortuitously removed a week before Christmas 2010; the last of the stained glass window finally extricated intact in December last year; shutters over deconstructed gable walls; and threaded tensioned wires running along the Great Hall ceiling pulling its gable ends taut.

"We are feeling quite vulnerable with this building at the moment," says Franklin calmly. "You can see the state of it. It looks reasonable externally but once you get in here you see that it is pretty fragile so the quicker we can get on to that permanent fix the better." The December quakes have hardened his resolve to move forward faster than ever.

This is the harsh reality of heritage recovery in central Christchurch. With so many heritage buildings already gone - in December, before the latest quakes, the Canterbury Earthquake Recovery Authority's (CERA) demolition list designates 124 "demolish", 22 "make safe", and 31 "partial demolish" - those still there are an increasingly rare commodity. Retaining the few remaining in the face of what seems like a scorched earth policy is a thankless, expensive task.

Hence the decision that enough is enough with the propping and that recovery can begin. "We estimate it will cost $240 million to strengthen and repair the site in total," says Franklin. "We're negotiating with two insurance companies - one has pulled out of New Zealand so we're now talking to their head office in the UK. There are a large number of reinsurers lining up behind them so it's a complex situation."

What's remarkable is that Franklin and the Arts Centre Trust Board - the body charged with preserving and protecting this iconic precinct - have somehow wangled the first $35 million of insurance money. That's enough for repairs and strengthening on the Clock Tower, including Rutherford's Den, and College Hall - a project estimated to take 30 months. Comprehensive insurance cover for the Centre was raised from $95 million to $116 million in January.

In December the Centre received an unexpected boost from the Christchurch Earthquake Appeal Trust - a $14m donation comprising $5 million from American philanthropist Julian Robertson, matched by $5m from the Ministry of Culture and Heritage and $4 million given by Fletcher Building. The extra money means Franklin is already planning stage two of the repairs - estimated at $30 million - for the former Christchurch Boys' High School buildings.

"This series of earthquakes is the worst thing that has ever happened to this place, but in a weird way it's also one of the best things," says Franklin with supreme optimism. "If we can get significant capital and inject that into repairing and helping to preserve these buildings in perpetuity, what a fantastic outcome that would be."

But it will be years before the public will once again enjoy the complex of bars, cafes, restaurants, galleries, studios, theatres, festival and event venues that the Arts Centre was. Heritage repair is a painstakingly slow business. For the Great Hall alone, all the slate roof tiles will be removed and a new plywood diaphragm applied, a concrete ring beam poured at the top of the walls, and the entire structure tied down with post tensioned steel rods.

In the Clock Tower some of the work is even more laborious, with new shear cores created inside the bluestone walls - a process whereby the internal masonry layers of brick or rubble are carefully demolished, replaced with reinforced concrete and then resurfaced with a brick facade on the inside. Elsewhere fibre reinforced polymer wraps - applied to the walls with resin and giving the equivalent strength of 100mm of reinforced concrete- will be used.