Phil Green: H G Rose Architecture

When a designer who thinks outside the “little boxes on the hillside”, collaborates with an established building industry leader to create a building reflecting the client’s ethos of quality and honesty, the result can be spectacular. 

The Certified Builders Association of New Zealand (now known as NZCB) was looking for a new tenancy in Tauranga for its national headquarters staff, the current tenancy being disjointed and lacking the cohesiveness required to function for service to its national members.

Several options were considered, including moving to another inner city commercial block, but NZCB settled for a parcel of land on the fringes of the Tauranga CBD which contained a single storey office area and an attached two storey steel portal warehouse/workshop bay and a generous, sealed parking area.

Foresight is a great thing: this area is now designated by Tauranga City Council as part of the proposed Tauranga City Revitalisation Plan and Marsh Street is to be rejuvenated into a boulevard of trees and walkways, thereby increasing the beautification of the area.

Phil Green of H G Rose Architecture was approached by NZCB to come up with some options for turning the existing building areas into office space as is but with future proofed facilities and a separate office area for another tenant associated with the building industry. 

It soon became apparent that the existing building footprint would not be suitable for office space dedicated to the client and considerable modification and earthquake strengthening would be required.

NZCB CEO Grant Florence worked with Phil to explore better possibilities to maximise the potential of the site. A revised brief called for re-use of as much as possible of the existing building footprint but allowing for two storeys across most of the building site. The outcome was to leave the south and east two-storey block boundary walls, to re-use as much of the portal frame steelwork as possible and to create a building that portrayed NZBC values and expertise. Also at issue was a requirement to work to strict heights and tight planning conditions given the adjoining properties form part of the historic precinct of Tauranga’s CBD. 

It became clear that a building with flair was required and the standard approach of a square or rectangle with some fancy detailing was not going to cut it. Phil’s vision was for a building that expressed the solid foundations of New Zealand construction techniques but also conveying the idea that NZCB were “qualified” visionaries in the industry. 

Phil set about sketching ideas onto paper and setting out rough plans. (Yes, sketching – no CAD in the initial stages). The first sketch designs explored the modernist approach of linear forms and simplicity and it soon became apparent that a more unconventional approach to this commercial build would be the answer. 

While working on the revised ideas Phil was, via another client contact, put in touch with the owners of a building in Auckland that was being demolished.  Skychefs NZ was demolishing their old premises and some very large and interesting timber work was available to purchase. Realising the potential re-use of some of these items, Phil asked the client to pre-purchase them even before the final designs were completed. It was a good example of the confidence and vision of CBNZ being able to visualise an idea working before it was  physically built.

Several 15m long curved laminated beams were transported to Tauranga for the new office project, Phil’s idea being for them to form the basis of an iconic look to the new building. With a grandfather who was a Master Carpenter/Joiner in Christchurch, and a father who was a farmer in Canterbury, Phil saw the potential of timber and its opposite, steel, being used to interesting effect. 

Grant, Phil and Allan Shaw (then President of CBNZ) met several times to discuss the designs and after some good collaborative meetings related to internal office layouts, the building design was locked in.

The design for the new building was to utilise all the skills available through Certified Builders and to showcase these where possible. The two-storey building has James Hardie flat panel walls, tinted office suite glazing and Colorsteel vertical cladding. 

It may look simple from the street but on closer inspection the detail is surprising. Walking onto the site one is confronted by ten tall, curved columns that are like guardians protecting what lies within.  This was Phil’s metaphor to the Maori Iwi who used to live in this area and their buildings and pa sites.  The area is also called “The Landing”, referencing where the first Maori tribes settled in the Tauranga area. 

Bold colours

The Resene NZ colours of the exterior are both earthy and bold to reflect the tradition of Certified Builders, but also their boldness in moving forward with innovation. The building has landed and is embedded in its site and appears strong and substantial, the tinted glass allowing subtle glimpses into the interior where movement and light can be observed.

Before construction on site began these curved, laminated panels had been sent away to be sandblasted, removing decades of dirt and grime and raising the grain of the panels. They were sealed and painted with a Resene paint system to enhance the timber effect similar to the ancient Japanese “shou sugi ban” technique.

Phil’s design was based around a steel column and beam exposed system harking back to the industrial use of the site and this is where some of the original steel was incorporated into the build.  The steel was coated in a smooth, fire retardant paint coating from Altex Coatings Ltd due to the steel having a prominent role in the design aesthetic. Tauranga based Tiaki Engineering Consultants were commissioned to design the entire structural components of the building from the ground up – literally the slab, new concrete block walls, steel/timber columns and beams, bracing and geo-tech work. 

Time stamps

The old concrete slabs on site were removed and certain parts of the site had to be excavated for geo-tech reasons as the land had formerly been an ancient beach before reclamation of the harbour to create an isthmus to link parts of Tauranga together. Above the site is the Elms, an historic mission settlement used by the first missionaries to Tauranga. Over the course of 100 years or so the site below the Elms was used as a waste deposit area so certain minor artefacts were uncovered and are now housed in the NZCB building as a time stamp.

Walking up to the front door of the NZCB headquarters one will not find a normal opening door system. The door slides away as part of a slanted curtain wall design. This caused some consternation with the local council at consenting time due to its shape and being literally part of the glass curtain wall design shape. At all times the design was considered with disabled users in mind and Phil consulted with local experts during early design stages to ensure compatibility with all users. Moving through the entry reveals a polished concrete floor indicating a solid base – NZCB ethos. At this ground level is the second tenancy area, meeting rooms and other facilities that can be used by anyone in the building. Anyone wishing to walk, run or cycle to work can avail themselves of changing and showering facilities that have been provided. 

The entry lobby is an atrium design with a connecting stair to the first floor where CBNZ is located. At ground level you are confronted by exposed steel columns and beams, timber ceilings and glazing. There are no ceiling lights visible with indirect lighting situated in the flanges of the steel beams which illuminate the area without glare to work surfaces. The ceiling has been kept lower than the usual 3.0 to 4.0m height but is 2.4m so more akin to residential spaces.

There is a large space dedicated to staff being able to relax with large, full sliding glass walls both internally and externally dividing the space into sitting, kitchen and outdoor entertaining zone. 

Phil worked with Nebulite Tauranga to create the right window suite for these areas – some of the sliding units meet at angles with no supports or posts to disrupt the space. Phil chose to keep the building height down using 220mm thick XLAM laminated timber floor panels resting on top of the steel beams, contributing to the fire design which incorporates a sprinkler system.

Up the stairs to the CBNZ tenancy, the space is not so much a reception area but is more like an after-work area where a trestle table sits with bar stools arranged around it. Behind this is a weatherboard-clad wall as if it had been dismantled from a house and re-inserted into the office. To one side are the “closed” office spaces for the CEO, personal assistant and the accountants. The other areas are as below with steel columns and beams but this time with a plywood modular ceiling. 

The original block walls to the south and east have been left rough and sealed with a clear system to demonstrate the past/present/future thinking of CBNZ. The same full height glazed wall extends up to this area showcasing the external court yard and the historic site behind the building which includes a hillside covered in historic protected trees. 

At the front of the building the CEO’s office juts out to the north and the staff facilities are at the front north side of the building allowing for views and sunlight. The roof extends over the outside entertaining area allowing for year-round use. 

External cladding

The versatility of roofing steel is well demonstrated when it comes to the external cladding of the building –the material (Brownbuilt 900 in MagnaFlow) chosen for locality and suitability. The material was used on the roof areas but on the walls, it was reversed – both vertically and horizontally doing justice to the strength of this material. Detailing for these design aspects of the build were paramount with Phil spending many hours with MRM and manufacturer Dimond Roofing to get the right connections between steel cladding, Hardies product and aluminium. The curved columns were particularly important where they interacted with the external cladding with specific detailing required to satisfy durability and weather tightness.

The wall cladding creates shadows so the building changes its dynamics over the course of a day, going from defined light and shade when the sun is at an angle to the wall face, to soft vertical lines when the sun is shining directly onto the face of the vertical wall cladding. 

At times some tricky design details on this special project for NZCB required some significant design changes but Hawes Building Solutions delivered competency throughout the duration of the job, their staff fully involved on delivering this unique building.