Leading the way in ecologically sustainable design, Conservation House is one of New Zealand’s most environmentally friendly buildings, using concrete alongside other natural features to strongly connect with the external environment.

Designed as New Zealand’s flagship environmentally proactive building, Conservation House (Whare Kaupapa Atawhai) is the first refurbished, equivalent five-star, green office building in New Zealand. Taking advantage of the unique properties of concrete, along with other materials and initiatives designed to reduce the environmental impact of both the building process and subsequent operation, the project team has created a benchmark for future building standards.

In searching for a new headquarters, the Department of Conservation (DOC) specified an environmentally friendly building that would engender a safe, healthy, comfortable and productive work environment for staff. After evaluating a number of proposed sites for the building, DOC selected the former Mid City Cinema complex, in central Wellington. “The building was chosen because it had the potential to provide an innovative, high-quality green building design, was priced competitively, and is in a location close to amenities and facilities that staff are already accustomed to using,” says general manager Grant Baker.

DOC’s fundamental principles for the project were: to optimise site potential; minimise energy consumption; protect and conserve water; use environmentally preferable products; enhance indoor environment quality; and optimise operational and maintenance practices.

Construction work was a major undertaking, requiring extensive planning and onsite synchronisation between numerous parties to ensure the project was completed on time, and with minimal disruption to the neighbouring businesses and residences.

The project’s complexity was due in part to the fact that the former Mid City Cinema is configured in an unusual “podium” shape that originally housed five theatres and a group of retail shops, above which is a separately tenanted office tower.

Working within the podium space, a significant demolition exercise was undertaken to remove multiple existing concrete floors. The situation was complicated by the building being situated in the middle of the city, close to occupied office and residential buildings, and was itself tenanted during the process.

The removal of the existing floors was central to the building’s open plan design. The creation of large atriums permit natural light to penetrate deeply into the floor plates of the multi-level office space, while exposed concrete ceiling surfaces are used as thermal mass to absorb excess heat during the day. Such passive design features are pivotal to the building’s energy conservation objectives, and overall sustainable aspirations.

New concrete floors were poured within the former cinema spaces, utilising the versatile tray deck flooring system. Stephen Cummings, McKee Fehl Constructors Limited project manager, points out that working within an existing building, with its numerous columns and floor slabs, made pouring concrete extremely difficult. The situation was compounded by narrow entries. As such all concrete was pumped into the building.

Concrete was also used in the construction of a new roof above what would become DOC’s cafeteria, conference room and roof top garden. Removing the original sloping roof was a particularly challenging aspect of the project, as in order to maintain the integrity of the construction site McKee Fehl poured the new concrete roof approximately one metre below the original one, which was then itself subsequently dismantled.

One of the most critical issues in the building’s refurbishment was the adherence to tight time constraints. Coordination of teams and the scheduling of activity were extremely important as these constraints affected when noise could occur. McKee Fehl overcame these limitations by carrying out noisy demolition work in the early evenings, and transferring all waste material offsite during the day.

As a symbol of DOC’s commitment to increase the value of conservation to all New Zealanders, Conservation House demonstrates the sustainable properties of concrete’s structural durability and thermal mass. The inclusion of concrete elements within its progressive design has contributed to an environmentally friendly refurbished building that will provide a safe, healthy, comfortable and productive work environment for DOC staff, as well as a benchmark for future environmentally proactive building projects.