The need for medium density multi-storey residential developments (apartments) in our main centres is more pressing now than ever before. Yet for a successful outcome to be achieved appropriate design and material selection that align with our unique requirements is vital.
To assist developers and their design teams maximise the opportunities afforded by the growth in apartments CCANZ has developed The Apartment Design Guide.
CHANGING DEMOGRAPHICS
Apartment living is becoming increasingly common in New Zealand, especially in the more densely populated cities of Auckland, Wellington and Christchurch.
While reasons for this include increased immigration and land constraints, the fact is that New Zealanders’ lifestyles are also changing.
There are more single person and couple households, more people renting because they can’t afford to buy, and more people moving in from the suburbs to enjoy the convenience of central city life.
There are also increasing numbers of retirees who want the ease of apartment living and who require less space after their children have left home.
THE DESIGN CHALLENGE
As a country we are still relatively inexperienced when it comes to apartment design. Copying international practice isn't always the answer. What works for someone in New York or Berlin won’t necessarily keep a Kiwi happy.
We value our connection to the outdoors, we like to drive, and we have bulky possessions, such as tools and sporting gear that require storage.
As well as providing extra room, New Zealand designers have the added challenge of tackling earthquake protection within the structural design.
ADDRESSING THE ISSUES
The position of a medium density residential complex within its surroundings, in terms of urban design, is hugely important. Communal zones (gardens and play grounds), access routes (vehicular, pedestrian and wheelchair) as well as discrete rubbish and recycling areas, are key considerations.
Another important aspect is the “type” of dwelling. Apartments can take many forms, such as detached, semi-detached, townhouse, terrace or loft to name just a few. Within the individual apartment envelope the number of bedrooms and room size must also be carefully thought through.
Linked to an overall design that is suitable for the local climate, uses correct detailing and is brought to life by skilled trades’ professionals, durable construction materials are paramount in an apartment complex. The consequences of any shortcuts in terms of quality materials will be magnified by the scale.
This is where concrete’s inherent properties, such as fire resistance and thermal mass, pay dividends for apartment investors, developers and residents.
Interior Climate
By using concrete’s mass with the sun’s heat, insulation and natural ventilation, more comfortable living conditions can be achieved with reduced reliance on space heating or cooling. An exposed, insulated concrete floor absorbs, stores and later radiates the sun’s heat, off-setting temperature peaks and troughs, to create a moderate living environment.
Sound Attenuation
Concrete’s high mass is also an effective means to attenuate airborne sound and protect residents from the disturbing influence of external noise sources, such as the neighbours low frequency (bass heavy) stereo system or the central city buzz.
Fire Safety
Concrete’s fire resistance helps protect property and preserve life during a fire. A 100mm thick concrete wall provides around 90 minutes of fire resistance, which is 30 minutes more than the New Zealand Building Code Clause C / AS2 requires.
Durability
As a durable material with low maintenance requirements, well-designed concrete structures can be expected to exceed their minimum service life as specified in the Building Code.
Concrete’s long life means it is more likely that a concrete building will come to the end of its life because no further use can be found for it (obsolescence), rather than the concrete having failed due to age.
Concrete also has the ability to resist extreme weather events such as flooding, which is predicted to become a more common occurrence. Concrete’s water resistance makes quick re-occupancy possible as cleaning, drying and repair are minimised.
Earthquake Protection
Reinforced concrete is leading the way in terms of damage resistant design solutions, such as PREcast Seismic Structural System (PRESSS), base isolation and non-tearing joints (slotted beams).
These systems represent a new low damage approach to seismic structural design for multi-storey buildings (including apartments), one which still embraces life safety as a priority, but also seeks to minimise damage and so enable continuity post-earthquake for building owners and residents.
It is anticipated that this low damage approach to seismic structural design will play an important role in the Canterbury rebuild.