Comment: There is one universal goal every architect and builder works towards when they undertake the task of designing or building a home in Aotearoa: comply with the New Zealand Building Code. I have shared in this ambition as a licensed builder, working on projects in Wellington for the past nine years.
But in my years of striving to do this, I have had to work with timber saturated in chemical preservatives, adhesives riddled with dangerous compounds, and paints that leave behind a legacy of microplastics. Despite their toxic nature, these are the materials we’re using to build ‘durable’ and ‘healthy’ homes.
This is not an experience unique to me: this is the experience of all builders, whether they are aware of it or not. A 2021 WorkSafe survey found that construction workers have the highest average number of exposures to carcinogenic (cancer-causing) substances, out of 30 professions examined.
The irony is undeniable: in striving to meet durability standards, we have normalised the use of materials that compromise human wellbeing and the environment we are striving to protect.
Designing differently
Wrestling with these issues, I was motivated to return to study and complete my Master of Architecture degree. My thesis explored design for disassembly (DfD) as an alternative to conventional durability standards. DfD challenges the notion of permanence by proposing that buildings should be conceived with their eventual deconstruction in mind.
As such, it offers a way of building that does not rely on chemical toxicity to achieve longevity but instead does this by replacing elements when they’ve reached the end of their life.
In practice, this might involve framing systems where individual studs and beams are removable and able to be repurposed without the need to demolish entire structures. It could also involve cladding that can be demounted and replaced rather than being permanently lathered in toxic coatings.
Materials would be joined with screws, bolts, or clips—rather than nail—allowing them to be separated at the end of their useful life.
During my research, I created a 1:1 scale model of a section of a building using a DfD approach. This model used untreated pine alongside materials salvaged from various building sites and recyclers. This scale model supports the idea that DfD is possible in the context of our existing construction industry.
However, such an approach would present a fundamental challenge to how we build now. We have conditioned ourselves to believe that fighting natural decay is necessary to achieve good building outcomes. But by forcing materials such as timber to resist their natural cycle of decay, we are creating long-term environmental hazards.
Carcinogenic preservatives such as copper chrome arsenate (CCA) don’t simply disappear once a building reaches the end of its life. They continue to leach into soil, water, and air, leaving a significant problem for us and future generations.
A lot of CCA-treated timber ends up in landfill. It’s estimated that 50 percent of waste sent to landfill each year comes from construction and demolition activities, with about a third of this waste being timber.
Although builders bear the brunt of exposure to treated timber, residents can also be exposed. Treated-timber products are often hiding in plain sight in decks and cladding. Many occupants are likely to have no idea that the structures sheltering them are built with materials that contain harmful chemicals.
Where to from here?
Our current system asks builders and residents alike to pay the price for durability standards that have failed to evolve alongside our knowledge of health and environmental impacts. This growing knowledge has led other jurisdictions, such as Australia, the EU, and US, to ban or restrict the use of CCA.
The idea of reducing timber treatments may leave architects and builders reeling, particularly given the leaky homes’ legacy still weighs heavily on the industry. However, at least in part, it’s our reliance on non-durable pine that has forced our reliance on treatments such as CCA. DfD provides the opportunity to consider both alternative non-toxic timber treatments and alternative timbers.
But for DfD to truly take hold, a shift must begin at the point where buildings are conceived: their design. We need to question not just our approach to design, but our planning of spaces to accommodate the demands of DfD.
There are plenty of examples from other countries that show how this problem can be tackled. For example, German architects C/O Now’s project ‘Where the wild morels grow‘ designed a residential building drawing on concepts of biophilic design and deconstruction. Biophilia in architecture aims to more closely integrate humans and nature. This project used the idea of a house built within a climate envelope (a house and garden sheltered by an external ‘shed’).
Of course, architects alone cannot achieve a switch to DfD. Considerable change is also needed within the entire building industry. Building regulations also need to evolve to encourage and reward circularity that considers end-of-life consequences, rather than measuring success through arbitrary lifespan targets for buildings and building components.
In addition, material suppliers must increase access to non-toxic, renewable, and recyclable products. Likewise, builders need to be open-minded and support new construction concepts and techniques that may be unfamiliar to them.
And lastly, everyone who has the privilege of owning a house needs to understand the impact they can have by choosing to support low-toxic solutions when considering renovating or building. It is time to let our buildings die a natural death and in doing so, give life back to the future of architecture.
This article was originally published on Newsroom.
Daven Candy is a Master of Architecture graduate from Te Herenga Waka—Victoria University of Wellington.