Asbestos halts BNZ House demolition
Asbestos has halted the demolition of an earthquake-damaged office building in central Christchurch.
Work bringing down BNZ House in Cathedral Square started in December but stopped a month ago when traces of the noxious building material were found.
Engineers found the substance encased in some of the building's concrete columns and isolated them while tests were done elsewhere.
The results were clear, but work has yet to resume as the discovery has forced a change in the demolition method.
BNZ House is a ''high-reach'' job, where massive excavators, sometimes known as ''nibblers'', eat away the building, as was done on the Christ Church Cathedral tower.
It will become a ''cut-and-crane'' job - where large sections of concrete are cut up and removed intact, similar to the Clarendon Tower demolition in Oxford Tce - once the process is designed and approved.
''Those specific columns will have to be cut and craned out to keep them encased and safe for easy disposal,'' a Canterbury Earthquake Recovery Authority spokeswoman said.
Hawkins is the project manager on BNZ House, and March McGee the demolition contractor.
Work is scheduled to finish in December.
The 13-storey building is set to be replaced with one of similar dimensions.
Consortium owner Cristo Ltd said the new structure, designed by Christchurch architects Warren and Mahoney, would be 50 metres high and feature glass walls and the same green Welsh slate as the old building.
It will include 11,000 square metres of floor space, including a penthouse, and could be finished by 2015.