Clearwater Quays Apartments

Entrant: 
Phillip Howard / Pacific Environments NZ Ltd

Category: 
4. Mid-rise building design award

Photographed by: 
Rachelle Grant (Exterior of Apartments), Four Walls Photography Ltd (Interior of Apartments)

The Clearwater Quays Apartments has a total floor area of 2,130 m2 (including garages) over five levels, with two open-plan apartments per level, overlooking the lakefront of the Clearwater development in Christchurch, New Zealand.

Clearwater Quays has a structural system which works to dissipate seismic energy. Designed under the structural engineers (Enovate) guidance, the methodology of the structure is a system of innovative seismic ‘H-frame’ LVL portals and beams which provide bracing in the east west direction, whilst in the north south direction, bracing is provided by the plywood lined light timber frame bracing walls.

The building sits on a raft foundation with a thick compacted gravel base which will help to limit any liquefaction. Lightweight CLT floors above enabled the five story structure over a relatively modest foundation compared to other structural typologies in Christchurch and throughout New Zealand. This was probably the most significant engineering challenge achieved using wood.

Timber created a cost-effective, fast, resilient and sustainable system for this mid-rise construction project. However, showcasing timber in apartment designs comes with its own unique set of challenges, particularly if you want to genuinely, express mass timber structural elements.

For example, acoustic regulations for residential apartments require floors and ceilings to be acoustically isolated from any timber floor structure which essentially prohibits the timber from being exposed and expressed. Inside apartments selective “H Frame” portals were left exposed, as opposed to the common circulation areas, which are relatively unconstrained by acoustic requirements, the timber structure and CLT stairs are expressed and highlighted through the curved entry form of the building. Here - a tall, glazed wall showcases the extraordinary CLT stair structure.

Engineered timber is not only naturally beautiful, but also provides a very strong, low carbon and comparably low-cost alternative to steel and concrete. It is easy to transport, relatively light, and has outstanding earthquake and fire resilience.

A case study for the Clearwater Apartments shows environmental benefits that cannot be ignored. The Quantity Surveyors (Logic Group) calculated the carbon for the mass-timber building as net negative 87,500 kilograms. If the building were to be built in traditional steel and concrete, it would have resulted in 800,000 kilograms of carbon being released into the atmosphere, and over 950,000 kilograms of carbon if concrete alone had been used.