As Green as an Emerald

September 9 2022

When the guest house at Emerald Bluffs was acknowledged in the NZIA Southern Architecture Awards earlier this year, it followed in the footsteps of its big brother – the main house on this property built in an Outstanding Natural Landscape, and a 2013 NZIA winner. We take a look back at its eco-conscious DNA…

RTA Studio was approached to design this substantial home because we had the credentials that mattered to them. Our commitment to sustainable design is long-held and the owners had seen the gold-standard model developed in the office in terms of residential architecture. That was the C3 house, commissioned by John May – the visionary behind the Emerald Bluffs development - a holistic carbon-zero building. C3 was designed to be carbon-zero to build and to run, and it is also 100% recyclable (an achievement for which it took out the Sustainable category at the World Architecture Festival in 2021).

The Emerald Bluffs house puts many of these principles of green design into practice, and presents them in a robust, pared-back palette of timber, stone, steel and glass. It may stand fortress-like against the elements, but its sustainable heart means it’s gunning for the planet.

Perhaps the most visually remarkable aspect of the home is the red-toned recycled tōtara cladding that runs along one side of the form to encase the main living zone. Sourced from Rotorua, this timber is from trees felled during the 1930s and 40s. The logs, which had been lying on the ground ever since, were found to have a fungal disease and fluted holes pitted their make-up. This ‘imperfection’ gives the timber a rustic charm which immediately allowed the contemporary home to look well-settled in the landscape. Locally sourced Otago schist anchors the base of the design squarely within the region.

Although the aesthetic makes an impression, it’s the hardworking operational aspects of the home that pump up its eco-conscious aspects. When you’re in a zone where the winter-cold can magnify energy bills, passive controls such as insulation and thermal gain become a clear priority. This residence has it all: concrete floors that skirt the perimeter are a heat sink; stone walls act as thermal mass; solar panels are perfectly oriented on a steeply pitched roof above the kitchen and master bathroom. There is also a wetback water heater and superb insulation to keep Jack Frost knocking at the door. And to top it all off, pebble ballast on the roof provides extra thermal mass.

Building covenants at Emerald Bluffs are integral to a wider commitment to a sustainable future in this precious environment on the edge of Lake Wanaka. The removal of wilding pines and the reintroduction of native fauna and flora is making great strides forward in restoring the ecological balance. It has been a privilege for the team to deliver the main dwelling and, almost a decade later, a guest house which are both very much in keeping with this important, far-sighted vision.

Projects mentioned in this post:

Emerald House Emerald Guest House C3 House