Sarjeant Gallery: Construction near as gallery finalises price and builder

From left: John Maihi, Greg Anderson, Gaye Batty, Fletcher Tabuteau, Hamish McDouall and Kym Fell.

As Whanganui celebrates the Sarjeant Gallery's 100th anniversary, the redevelopment project moves into the construction phase.

Firstly we'll be consulting on the groundworks for the design and construction of temporary road access and parking for the neighbouring buildings – the Whanganui District Library, the Alexander Heritage & Research Library and Brass Whanganui.

The Sarjeant Gallery at the top of Pukenamu Queen's Park is currently closed for earthquake strengthening and construction of a new wing – Pataka o Sir Archie John Te Atawhai Taiaroa. While the construction work will happen in two parts – a new wing, and seismic strengthening and refurbishment of the original building – the new institution will open and function as one integrated building.

After a series of physical inspections of the building and an updated geotechnical ground survey, the project design team has selected the Post Tensioned Strand (PTS) system for seismic strengthening. PTS involves embedding steel cables in the walls to create a stronger structure with the same characteristics as a reinforced concrete building. The PTS method is less invasive than the base isolation system that was proposed in 2016 and will ensure preservation of the internal heritage valued finishes and decorations of the building, like the plasterwork.

Redevelopment director Gaye Batty and Parliamentary Under-Secretary for Regional Economic Development Fletcher Tabuteau at the Sarjeant Gallery on its 100th anniversary, 6 September, 2019.

In June, we went out to tender for the lead construction partner and received a strong level of interest from construction companies around the country. We are now working through the final stages of the RFP (Request For Price) process and expect to announce the lead construction partner later this month. Until that announcement, all costs remain commercially sensitive.

During the detailed design process, it became clear that inflation in the construction industry would have an impact on our 2016 cost estimate of 34.9 million. We have been pursuing alternative lines of funding to make up the expected difference, including being awarded the recently announced $12m contribution from the Government's Progressive Growth Fund.

We're working to ensure there is sufficient contingency funding available throughout the 2.5-year life of the project and the Sarjeant Gallery Trust is committed to continued fundraising.

• Gaye Batty is project director of the Sarjeant Gallery redevelopment.