Work on a Canterbury Category 1 Historic Places Trust building which started out as an $800,000 repair job after the Darfield earthquake became a full $5.8 million restoration project following the second major Canterbury earthquake in February 2011.
The attention to detail and care used to restore Strowan House at St Andrews College in Papanui, saw Bushnell Builders Ltd win the Restoration Category and awarded Gold at the 2014 New Zealand Commercial Project Awards.
Bushnell Builders director Matthew Bushnell says this was the most challenging project his firm had ever undertaken in its 35 years.
“The amount of labour involved — 46,000 man hours — was huge,” Mr Bushnell says.
“It all had to be carefully pulled apart, labelled and stored before the rebuild. There were no surplus storage facilities, so we had to build temporary storage adjacent to the site,” he says.
Bushnell Builders was originally contracted in September 2010 to repair the damages caused by the Darfield quake and to install a sprinkler system for a fire upgrade. They were two weeks away from completion when the February 2011 earthquake hit.
Working with project partners Wilkie and Bruce Architects Ltd, Holmes Consulting Group Ltd, Paul Bunkall of Rawlinsons Quantity Surveyor, and Powell Fenwick Consultants Ltd, Bushnell had the complex task of a full structural upgrade, repair and refurbishment of the entire building, complying with strict resource consent conditions, all while ensuring the historic value was maintained.
“The scale of work and the fact that the repair strategies were developed as we went contributed significantly to the challenges,” Mr Bushnell says.
“The engineers would come up with a different structural solution for each area as we progressed — there was no master plan. We knew we had to restore the whole building, but we didn’t know the work that was involved with each section until we were doing it.”
Due to the delicate nature of the building, much of the excavation had to be done by hand. This often exceeded 1.2m in depth, with a total of 200 cu m of spoil being removed by hand.
Foundations were rebuilt in very small sections to ensure the existing structure maintained its strength, and all but one plaster lining had to be removed due to cracks in the plaster compromising its integrity.
The new state-of-the-art sprinkler system, extensive structural upgrading and retention works have all contributed to a strong and secure future for Strowan House. All the hard work and long hours are almost undetected, which Mr Bushnell says is a true testament to the care and attention given to detail.
“All the services that are required to enable a building to have a modern day use have been fitted and discreetly concealed. So you’ve got a building that is stronger than it ever was, that’s better protected than it ever was and which is better suited for long-term usage, but still looks the same,” Mr Bushnell says.
