Removal of huge original chimney a feat of engineering – Canterbury Provincial Council Buildings

The expert opinion of a structural engineer and a stonemason established that the huge original chimney at the top of Canterbury Provincial Council Buildings needed to be removed. Both the stonemason and engineer have previously worked with the Buildings. They worked out a methodology for removing the chimney’s top 2.5 metres in one piece, to minimise further damage and to preserve its integrity. The stonemasons, who undertook repointing work on the Buildings in 2009, have a thorough knowledge of the Building’s stone work and construction.

The chimney will be reinstated at a later date.

The chimney was lowered on to a large ‘pin’ waiting in the courtyard after some spectacular stone cutting. The piece is 2.5 metre high and weighs between six and eight tonne, requiring a 100 tonne crane.

The central chimney was stabilised soon after the initial earthquake when scaffolding was erected. Although previously strengthened with concrete and steel - and therefore at no risk of falling - the chimney’s movement loosened the courses of stonework at its intersection with the gable. In order to effect repairs and make the Buildings safe again, some of the chimney’s stonework was sawn through, then lift off as a single piece, and placed in the Buildings’ central courtyard.

Once it has been determined that the Canterbury Provincial Council Buildings have been made safe, all areas currently closed will reopen to the public. 

The Buildings hold the highest heritage listings with both New Zealand Historic Places Trust Pouhere Taonga (Category 1), and Christchurch City Council (Group 1, Christchurch City Plan) for their international and national significance.

The Canterbury Provincial Council Buildings are the only purpose-built provincial government Buildings still in existence in New Zealand. The Building was constructed in stages between 1858 -1865.

Background to lifting of Canterbury Provincial Council Buildings’ original chimney

Well known heritage site in the Central City, Canterbury Provincial Council Buildings, has undergone stabilisation of its huge central chimney.

While a Level 1 assessment resulted in an initial green placard, a subsequent assessment resulted in the Stone Chamber receiving a red placard. A red placard means people should not enter or occupy the home/building because it has been determined unsafe. It is not a demolition order. Remaining sections of the complex has received a green or yellow placard with some restrictions on entry and use. The Belgian Beer Café and tenant office areas are open for business.

As a result of the initial earthquake there was significant damage to the northern gable. This included damage to the gable wall and capping above the street entrance nearest to the Stone Chamber. The lower part of the central chimney also sustained damage. Thanks to earthquake strengthening in the 1980s the central chimney remained relatively stable preventing it from falling through the roof into either the Timber or Stone Chamber. Subsequent aftershocks resulted in damage to the southern gable and to some of the internal arches in Bellamy’s corridor.
 The two landmark companion chimneys on the southern end of the Stone Chamber suffered comparatively little damage because of a significant programme of restoration fortuitously completed in 2009.

As the buildings’ heritage recovery moves forward, successive Christchurch City Council commissioned conservation plans for the building, the latest completed in 2009, will provide invaluable information.