Conservation architect Chris Cochran shares his views on the redevelopment of Whanganui's Sarjeant Gallery

Conservation architect Chris Cochran at the Sarjeant Gallery.

On-site at the historic Sarjeant Gallery Te Whare o Rehua Whanganui, conservation architect Chris Cochran recently shared his knowledge and appreciation for the beauty of the old and the innovation of the new.

A specialist in the treatment of heritage buildings, Cochran has been commissioned by Whanganui District Council to ensure the gallery's redevelopment meets New Zealand's heritage values.

The redevelopment of the historic 100-year-old Sarjeant Gallery involves earthquake strengthening the existing heritage building and construction of a new wing – Pataka o Sir Archie John Te Atawhai Taiaroa, named in honour of Sir Archie Taiaroa. Cochran said the project architects, Warren and Mahoney, have designed a discreet connection to join the new building at the back of the old building so they will work together and yet stand as distinct works of architecture in their own right.

"It's a wonderful juxtaposition of old and new I think," he said.

"Somebody who knows the building today will be perfectly happy and excited to see the building in its refurbished form. It will be built to meet new building standards, and fully serviced so it will be available for all sorts of art exhibitions. It will set the place up for another 100 years, at least."

What you see today will largely remain after the refurbishment despite the serious structural work to be done. While there is some "intrusion into the fabric of the building" with air-conditioning and earthquake strengthening, it's being designed carefully for minimal disruption, he said.

For example, inventive classical details included by the original architect Donald Hosie, such as solid push plates and door handles, carry on the classical tradition of the building's exterior.

The building is strongly axial – north south, east west – completely symmetrical. At the centre of the four main arms of the building is its masterpiece space, the great dome with natural light coming in on four sides.

A conservation architect visits the Sarjeant from Sarjeant Gallery on Vimeo.

"It's beautifully and subtly ornamented – it's a lovely gallery space," said Cochrane.

"The building is a work of art in its own right. I think [gallery] directors have understood that it's not just about the collection but actually the Sarjeant Gallery itself. It's an absolute treasure."