It's in the post

Auckland’s refurbished and repurposed former Central Post Office anchors the new Britomart station in the existing fabric of the central city.

A grand old building forms the public face of the modern Britomart Transport Centre. The former Auckland Chief Post Office, completed in 1912, forms an important link between Queen Elizabeth Square and the new station. Downer Construction worked on the refurbishment of the building, from the strengthening of its structure to the restoration of its facade. The Coromandel granite and Oamaru stone on the west facade and rendered plaster work on the other sides were carefully restored, and new roof installed above the central light well.

Contract Coatings applied Resene products throughout the restored CPO, Auckland.
Downer Construction was contracted to refurbish the former CPO building, which fronts onto Queen Elizabeth Square. The building also had to be strengthened, to meet modern seismic standards, and the interior renewed. A 20m x 12m hole was cut in the back of the building to link it to the station. This had to be supported by a new concrete lintel and columns, and underpinned by new screw piles.

Resene Engineered Coating Systems are designed to withstand demanding environments subject to harsh weather conditions, corrosion or graffiti.
Refurbishing or replacing the CPO’s many windows fell to Crittall Arnold, manufacturer of fire-rated, glazed commercial installations and architecturally designed residential steel windows and doors. All windows were grit-blasted, sprayed with hot zinc, and then sealed with Resene Armourcote 220. Where necessary, they were partnered with new bronze replica hardware from Cambrian Engineering.

Downer strengthened the structural shell of thebuilding with an internal, reinforced concrete skin up to 400mm thick. Additional steel bracing was also added to the existing timber floors. The former ground floor of the building was lowered around 1.5m to increase the stud height. An underground concourse below it now runs from the station to the western side of the square. Senior project manager Dale Burtenshaw says one of the biggest challenges was cutting a 20m x 12m hole in the rear facade to link it to the glasshouse, while supporting the building structure above.

Steel joinery specialist Crittall Arnold was approached to refurbish or replace the casement windows of the former Chief Post Office, many of which had not been adequately maintained over the years, says company director Darren Arnold. "In conjunction with the heritage architects, we grouped the windows into three categories: those that needed replacing completely, those that needed to be removed and rebuilt in the factory, and those that could be refurbished on-site," he says.

As the original steel window section is no longer available, efforts were made to source a similar profile from Canada. However, when this proved infeasible, the solution lay in customising Crittall Arnold's standard W20 profile to mimic the existing window sections. Much of the window hardware was also dilapidated, although many of the original pieces were able to be refurbished, recoated and re-installed. Where this was impossible, Crittall Arnold commissioned Cambrian Engineering to manufacture replica bronze hardware.

Much of the glazing throughout the former CPO was undertaken by Woods Glass. This was not the first time the company had worked on a heritage project with Downers, says general manager Matthew Harris.

"We were engaged by Downer Construction on the Auckland Town Hall, which was another complex project in a building of a very similar age to the CPO," he says. "We have also been extensively involved in the refurbishments at the Auckland War Memorial Museum."

So Woods Glass is no stranger to the complexities of retrofitting modern glass installations to heritage buildings. The key challenge, says Harris, is the attention to detail required by such jobs. As no element of these older structures is standardised, each installation needs to be considered independently and then custom-made. Because of this, the firm was consulted by architects Jasmax at the design phase of the CPO restoration.

Here, Woods Glass's handiwork includes the supply and installation of the canopied entranceways from Queen Elizabeth Square and all the Dorma Horizon frameless automatic doors. The company can also put its name to the translucent, glass column boxes and display cases mounted around the feet of the columns, as well as glass stairs, balustrades, lighting boxes, mirrors and vanities. The existing windows on the external face of the building were all reglazed, and the glass in the atrium roof was another key element of the job.

"There's really not a part of the building where we haven't been involved in one way or another," says Harris.

Resene worked closely with the architects to specify its range of Engineered Coating Systems to best suit each area. For example, steel window frames were sealed with Resene Armourcote 220, then topcoated in Resene Uracryl 403 in white. Silver Grey Aluminium Resene Uracryl was used on the bus shelters, while Resene Imperite IF 503 Metallic Aluminium was used on the glasshouse structural steel.

At the former CPO, Woods Glass’ shandiwork includes the supply and installation of all the Dorma Horizon automatic doors and the canopied entranceways on Queen Elizabeth Square.

Woods Glass, in conjunction with Thermosash Commercial, also supplied glass for, and glazed the atrium roof in the centre of the CPO. This open space lets light into the middle of the building and protects the historic, coloured glass domes in the ground floor ceiling.

With a project of this size, it wasn't just a case of slapping on a few coats of paint. Careful attention was paid to specifying Resene Engineered Coating Systems products. The team from Resene worked with the architects to prepare a coating specification, estimate quantities and select colours. Resene Engineered Coating Systems are designed to withstand demanding environments subject to harsh weather conditions, corrosion or graffiti. The steel window frames in the former CPO and the bus shelters outside were both coated with Resene Armourcote 220 to seal off surface porosity, before being topcoated with Resene Uracryl 403, a long-life, high-gloss urethane-acrylic finish.

The structural steel components of the glasshouse link are also sealed with Resene Armourcote, then given a metallic-look finish with Resene Imperite IF503. Resene marketing manager Karen Warman says the company's Metallics range, showcased in the Resene Metallics and Special Effects colour chart, is becoming increasingly popular, with 43 shades available for interior and exterior applications.

Applying the paint fell to Auckland-based Contract Coatings, a commercial painting firm specialising in large-scale assignments.

The company won the contract through a combination of competitive quoting and performance history, says managing director Peter Heaphy, and its input was sought when developing the painting specification. It was important that there was a complete understanding of what would be required, especially in the case of the steel windows, says Heaphy.

Contract Coatings applied Resene products throughout the restored CPO, including the walls of the atrium light well and the steel frames of the atrium and glasshouse.

The firms worked together to ensure that the systems specified were those best suited to each area.

The CPO restoration is not the first heritage project on which Woods Glass has worked with Downer Construction.

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