OPINIONSocietyApril 5, 2024

We can’t afford another leaky homes crisis


The government has announced plans to encourage international products into the New Zealand construction industry. Architect Mat Brown looks at the complexity of this proposition and whether anything will change.

On June 14, 2017, Grenfell Tower, over a period of two and half days, burned from bottom to top.  Seventy-two people died. The investigation that followed would describe a complex combination of factors that led to the fire starting and spreading.

One of the factors that contributed to the spread of the fire was that, in response to market forces, materials had been substituted in isolation. Meaning materials had been swapped out to save money without a full understanding of their contribution to the whole design. In some instances the use of those materials was so far removed from the testing that underpinned their compliance that they hardly bore resemblance at all, negating the test’s validity.

It might be easy to think that buildings are simply made from an assembly of materials but the reality is that they are complex systems. Those materials work together to perform a variety of functions. That might be to protect inhabitants from fire, stop the building’s collapse in an earthquake, or give the consumer some confidence that the building will be durable and a safe investment.

The remains of residential tower block Grenfell Tower are pictured, in west London on June 15, 2017, a day after it was gutted by fire. (Photo: TOLGA AKMEN/Getty Images)

New Zealand, of course, has had its own construction disasters. The leaky homes of the late 1990s and early 2000s were the result of thinking about materials in isolation. The designs, when put to the test in real life situations, failed. Mould grew, hidden in our walls, making people sick and eroding assets. The cost has been estimated as being up to $23bn, affecting nearly 90,000 buildings.

The announcement yesterday that the government will open our market up to internationally proven products is encouraging, but clearly not informed by an understanding of how buildings work and the reality of our industry. Given the nature of the announcement it may be surprising for some to learn that New Zealand doesn’t restrict the use of any materials, international or not. All you need to do is illustrate that their use, as part of the whole design, is going to keep people safe and healthy. There are many ways of meeting those thresholds, including reference to international standards and precedents, the exact thing that minister for building and construction Chris Penk spoke about yesterday when explaining that overseas standards equal to or greater than New Zealand standards would be accepted.

After 20 years of using the current Building Act (being a tweak of the 1991 Act which was similar in structure) the industry has found its equilibrium. Councils, designers and builders have shuffled and adapted to manage their risk, responding to the market forces that have manifested over that time.

One of those adaptions is councils’ response to spending much of the early 2000s in court and paying out large sums to leaky home owners, some of whom are still awaiting settlement. Councils can’t accept the risk of a design failing, and yet the Act requires them to. When asked to assess whether a design meets compliance standards, they want proof, and rightly so.

The industry has become increasingly reliant on tested systems. In the case of a pipe passing through a plasterboard fire wall, that means that the whole assembly must be tested to show that the timber frame, plaster board, insulation, pipe and fire collar all behave in a way that keeps people safe when exposed to fire.

The industry, in response to tightening compliance pathways, has invested significant amounts of money, to have their products accepted by councils across the country. Under the initiative announced yesterday, it would seem that councils will be forced to accept substitutions. Those substitutions must meet a recognised standard, but the inference is that new tests won’t be required. Is it the same system if we replace one product? Two? All of them? What about if we take that newly consented system and replace something again?  At what point does it stop being the proverbial grandfather’s axe?

In the end, councils (rather than central government), as Building Consent Authorities, control the use of building materials. With 73 of them across the country, changing the way they behave in response to 20 years of using the Building Act will be no easy task. Suggesting that Consenting Authorities will be forced to accept alternative products is another way of saying that they will be forced to demand new tests. When considering the sheer number of permutations that might be required to sufficiently expand the pool of building products in New Zealand, the cost is unfathomable, and ultimately passed onto the consumer.

There’s nothing stopping existing manufacturers from doing these tests now. The answer is less clear than it might seem. In 1991 the Building Act was internationally recognised as being an innovative leap into the free market. It embraced and continues to enable the sort of competition being described in yesterday’s
announcement. The reality of its application cost us in many ways. We’re yet to see the detail of the government’s plan to “cut red tape”, but the manner in which it manages the risk of failure will be critical.

Hopefully any savings won’t be at human cost, as it was at Grenfell.

Keep going!