The need for medium density housing
There has been a bit in the news on medium density housing in the last few years, probably along with some confusion as to what it is. For example, many reactions to a recent council proposal were based on the assumption that it was a social housing project, but it was merely a suggested change to the District Plan for certain residential areas. In fact, medium density housing has a much wider purpose than just getting people into homes, though that is important. Here, we detail some of the benefits...
Firstly, what is medium density?
BRANZ has adopted the definition of medium density housing as multi-unit dwellings of up to six stories (above ground) with three categories:
1-2 storey attached houses (eg duplexes, triplexes, semi-attached terraced houses)
2-4 storey attached houses (terraced houses)
3-6 storey apartments
High density housing has been a global coping mechanism for large populations for a long time. Medium density solutions offer a reasonable compromise for those of us (Kiwis) used to having room to swing a cat.
Guy Marriage talks in his wonderful book "Medium" about the area of land used to fit dwelling units (du) on. So if the 1/4 acre dream has 10 du/ha, then 3 separate two-storey houses on a 1/4 acre section would give 36du/ha, and 3 storey semi-detached terrace houses provides 50du/ha, while apartment housing can give even better density.
Of course it's a case of horses for courses; the site location and restraints must be factored in for an appropriate design solution. We also acknowledge there is a need to retain important urban fabric and identity of place that could be lost with a carte blanch overhaul, such as areas with a certain historic style.
The UK is known for its rugged and monotonous terraced housing (above), but New Zealand’s sparser cities have an opportunity to create unique urban intensification solutions, such as Vinegar Lane in Ponsonby, which is projected to generate 280 du/ha.
Bearing all that in mind, we see medium density housing as a means to the following:
Housing at a lower cost
With our housing and cost of living crises, it makes sense to fit more dwellings in our current urban centres. The efficiencies of existing infrastructure and small, joined dwelling units combine to provide housing at a lower cost. Using technology and prefabrication where able can make it even cheaper.
Carbon efficiency
Utilising existing infrastructure (roads, pavements, services) avoids all the carbon required to build new suburbs further out from city centres. Joining buildings as much as possible also creates efficiencies by avoiding building extra walls. Similarly, attached dwellings have fewer external walls, which is great for thermal performance (reduces heat loss).
Transport reduction
By keeping housing in arterial routes or city centres we can reduce travel times and cost in getting to work or amenities. Walking, cycling, and public transport become much more viable options.
Creating a community
Of course for medium density to work well it must be designed well. It's not just about building smaller but building smarter. Quality indoor and outdoor spaces are needed, with privacy and connectedness between dwellings -- both visually and acoustically. Joined dwellings ensure outside space is maximised for useable amenity (rather than wasting space on narrow side yards). Access to communal spaces or nearby amenities is required to provide an appropriate standard of living.
Resilient structures
The devastating weather events this year have shown us the need to be more resilient in our construction -- not building in areas that are prone to flooding, overland flow paths, or locations with unstable ground. While the building code is set to protect human lives (being able to escape in an emergency) that doesn't promise the building itself will ultimately escape demolition. Nor does it take into account the emotional toll of losing possessions or major remedial work to a property, as well as the significant increases in insurance. So we do really need to consider medium density housing from this aspect and, perhaps, retreat from riskier areas to prefer greater population concentration.
So is the 1/4 acre dream dead?
Probably in most cases. We need to shift away from the separate building model as much as possible. It's time to embrace the efficiencies of medium density as our future to provide housing with the benefits of reduced carbon emissions, ease of transport and a sense of community that will last.
