Green Build: The fabric of sustainable construction

Buildings and construction make up a fifth of New Zealand’s carbon footprint. This means that without significantly reducing the industry’s carbon pollution, the country’s international obligations on climate change won’t be met. But things aren’t all doom and gloom with many in the Kiwi construction industry leading the way to ensure a greener future for New Zealand.

The first manmade structures were formed using materials gathered from the land – namely branches and sticks, mud and stone. Today of course, we have come a long way from this. But we are circling back to using materials and methods that are kind to the planet.

In 2019, the world saw the highest ever level of emissions from the construction industry. Closer to home, New Zealand’s built environment is responsible for 20% of the country’s carbon footprint.

“If we want to meet our targets, we absolutely need to reduce those quite fast especially as we are building more and more buildings and homes,” says Andrew Eagles, New Zealand Green Building Council’s (NZGBC) chief executive.

And steps to do so are already being made.

MBI’s Building for Climate Change report published last year found that 92% agree the sector needs to take action to reduce emissions, and 87% believe initiatives to reduce whole-of-life embodied carbon in buildings should be included. To achieve carbon neutrality by 2050, the Building for Climate Change Programme has been set up to reduce greenhouse gas emissions during the construction of buildings, and throughout their operational life.

Many Kiwi companies are doing their part. By developing sustainable construction products, offsetting their emissions and making greener choices, these are some of the companies leading the way to a climate resilient future for New Zealand…

Reducing embodied carbon emissions

NZGBC’s chief executive, Andrew Eagles, says that reducing reliance on fossil fuels is a major step the industry needs to take.

With over 520 members, the NZGBC is a not-for-profit representing companies and organisations “who believe we can transform our built environment; from large government departments, banks, energy companies, and insurers, to property and construction companies, architects, developers, designers and tertiary education providers”.

The organisation helps to educate, advocate, and rate the sustainability of buildings.

Courses are provided for the sector, including monthly webinars on materials, example projects, and new technologies that can help reduce impact on the environment.

“And then we have formal training courses on the agreed steps or methodologies for measuring impact in New Zealand, so that is Green Star, Homestar, Neighbours – those sorts of tools where you sign off on things which are green,” says Eagles.

When it comes to advocating for change, NZGBC provides “research and input and advice to officials about how the building code can be changed, or labels for buildings and actions on embodied carbon”.

“We show people that change is possible by rating buildings that are more sustainable. We have over 10,000 homes being built to Homestar and hundreds of buildings – over 200 now – built or being built to the Green Star standard.”

Using these ratings, Eagles says that they then show others how these buildings have been built so the sector can learn and see that it is possible to change the building code.

One such building that NZGBC is using as an example, is 82 Wyndham Street, Auckland, which has become the first building to be awarded Toitū carbonzero certification by NZGBC and Toitū Envirocare. Owned by NZX listed property investment and management company Argosy Property Limited (Argosy), the award makes it the only building in the country to comprehensively record and measure their operational carbon footprint, create set targets for improvement, and entirely offset their emissions.

“The certification is based on how energy efficient the building is when it’s in operation,” says Eagles.

Throughout 2020, the 6,000m2 building’s base services were monitored, its fuel use, electricity, water, waste and refrigerants recorded and tallied to paint an accurate picture of the building’s operational footprint over 12 months.

After recording all of these measurements, the remainder was offset to gain the carbon zero certification.

Eagles says that this step – reducing operational carbon emissions – is key towards creating a more sustainable built environment for New Zealand.

“Then the other thing if you are building is to start thinking about reducing your embodied carbon emissions – concrete and steel and those sorts of things. If you want to do well, you’ve got to get off fossil fuels.”

However, one of the challenges with this is that the thinking around building with lower embodied carbon materials is still very new.

This means that for those who are used to building with the likes of concrete and steel, “they are going to need to think about moving to greener concrete, or potentially using lower embodied carbon materials”.

Using the resources we already have

One Kiwi company that will soon be providing the industry lower carbon building materials is SaveBoard.

Back in 2017, Fonterra and EnviroWaste were looking for ways to help divert some of their Tetra Pak and other packaging waste that is created as part of the manufacturing process. After visiting the US, a technology that offered a solution was identified – a low-carbon, environmentally sustainable replacement to plywood, made from packaging waste such as used beverage cartons, soft plastics and coffee cups.

However, as Paul Charteris, CEO and co-founder of SaveBoard explains, neither were in a position to actually bring the technology to New Zealand as “it’s not their core business”. This is where Charteris stepped in.

“I was approached to look at how we could bring the technology to New Zealand with their support,” says Charteris.

After getting involved in 2018, the chartered mechanical engineer spent a year performing due diligence for the building material, “which included bringing in samples, doing some screening tests to see its suitability with the New Zealand building industry and doing some tests around that”.

This process also included visiting Iowa, US, to see the product in action.

“I spent about a week over there and brought back a whole bunch of samples and used those to really sort of tease out the market to see what the market appetite would be to bring such a technology to New Zealand and what the appetite would be for purchasing the finished products.”

Over a two-year process, Charteris self-funded the project to get the ball rolling. During this time, he performed thorough testing, worked to close gaps and questions that potential interested parties had, developed a comprehensive information memorandum, and connected with companies and individuals he thought would be complementary.

“And each time I got pushed back, I would use that as an opportunity to close the gaps,” says Charteris.

COVID-19 dealt a major setback when a potential major investor at the time had a “few speed wobbles and had to pull out and not go through with the deal”. But again, this push back helped get the brand to where it is today.

“I did a bit of soul searching and thinking outside the square. I managed to connect with two Australian companies called Med-X and Shred-X which are actually subsidiaries of Freightways Limited.”

After connecting with Mark Troughear, CEO of Freightways New Zealand, as well as general manager Neil Wilson, Charteris sent them some samples of the technology – this led to Freightway’s investment in SaveBoard.

Charteris had also been speaking with a number of other investors at the same time, including Closed Loop.

“Then also Tetra Pak put in a financial contribution to get it up and running as a commitment to the business and they have product stewardship of the waste cartons that they’re bringing into the New Zealand market.”

This support from Tetra Pak, together with the investors, is what “made it a reality” and means that SaveBoard is ready to start distributing its technology to the New Zealand market in November.

Once the New-Zealand made 100% recyclable boards start appearing on building sites, Charteris hopes they will contribute a positive difference to the industry.

“It’s something that’s proven, and it makes a real difference to diverting packaging waste that would normally go to landfill. The other benefit is that it reduces the downstream construction waste that’s generated on a building site because we can actually take back all of our off-cuts and remanufacture them into new boards – it’s a great circular outcome both for the packaging material and the end products.

“This doesn’t really exist for many products in New Zealand. You only have to walk past a construction site to see all these waste bins filled with raw material.”

By purposefully not making the product more expensive than traditional building materials, Charteris says SaveBoard will give Kiwi construction companies the opportunity to “make a sustainable choice without paying a green premium”.

“We can’t keep going on with burying things in the ground and think it’s all going to be okay.”

Creating a circular system

Winstone Wallboards is also committed to doing its part in providing New Zealand construction sites with a more environmentally friendly building option.

The New Zealand-based company’s GIB Plasterboard is made from naturally occurring gypsum which can be recycled.

But it’s not just the product’s life while in use for construction that is considered. Winstone Wallboards actively considers the full lifecycle of its products and supports recycling initiatives both from the manufacturing process as well as general site construction waste.

“At our Auckland site, all waste material that is generated from the manufacturing process will go to companies like Green Gorilla,” says Gordon White, Winstone Wallboards’ residential market manager.

And because of gypsum’s composition, White says it is a good soil reconditioner and can be reprocessed into horticultural and agricultural-type products once collected by waste providers.

“Gypsum as a material can be widely used throughout New Zealand given its positive benefits in terms of improving soil quality such as being used for applications such as clay breaking. So, the good thing is that when we’re starting with that material in plasterboard, the base material is actually a highly sought-after product in terms of reuse,” says White.

The same applies for the company’s Christchurch site.

“We work with another composter in the Christchurch region, and they essentially take our waste product from the production site as well as from new build construction sites and mush it up into little bits and reuse the gypsum content in the product in a range of agricultural products.”

While these types of services are currently limited to Auckland, Christchurch and Queenstown, White says that “the long-term goal is to work with regional waste businesses to develop similar options in other regions where it’s feasible to do so”.

As well as this, Winstone Wallboards’ is working with the wider construction industry to help create industry tools that are focussed on minimising waste at the outset.

“It actually is everyone’s responsibility – it’s not just the waste provider’s, trade customer’s or supplier’s job to try and deal with construction waste, it needs to be a more collaborative approach to find suitable outcomes to the issue.”

White says that a lot of the material you see in skip bins at a construction site hasn’t been used and that this can be expensive for customers.

“A lot of customers don’t actually realise how much unused construction product from their sites is going to landfill which is costing them a sizable amount of money. Customers may factor in a level of waste into a job’s cost, but typically when we look at the data, we tend to see the level of actual waste coming off the site is considerably more than their cost estimates have allowed for.”

The good thing, says White, is that the idea of the industry working together to be more sustainable is starting to gain momentum. But as with most things, this takes time.

“Even if you minimise the amount of waste created on site, the second part of that conversation is what you do with the waste you do actually generate on site, rather than having it go to landfill.

“While New Zealand’s got a reasonable amount of space, those landfills are filling up pretty quick and homeowners and customers don’t really want to have another landfill sitting on their doorstep.”

By taking product stewardship, Winstone Wallboards is doing its part in helping the industry take a step in the right direction.

Next on the agenda for the company is introducing a new plant in Tauranga.

“When it opens in 2023, it will replace the Auckland site and will reduce our carbon emissions by starting off at about 10% and growing from there, but it will also enable us to take some of those offcuts that are being generated on site and reuse them as part of the manufacturing process.

“There’s a lot of things happening.”

A greener path

But it’s not just choosing sustainable building materials – transporting the building materials to site also factor into the emissions the industry creates.

The Sustainable Business Council’s (SBC) Freight Group recently released its Low Carbon Freight Pathway report. Ambitious but achievable, the report sets out a 30-year pathway to progressively decarbonise New Zealand’s freight system. The goal is to achieve this by reducing emissions by optimising the use of existing vehicles, replacing fossil fuels with biofuels, and replacing retired vehicles with zero carbon vehicles.

When it comes to transporting materials, Christchurch-headquartered cryocooler developer AFCryo provides a “cheaper and more reliable way of generating green hydrogen from renewable sources for refueling transport” as well as generating power and for industrial use.

In partnership with UK manufacturer Clean Power Hydrogen (CPH2), AFCryo recently unveiled its Green Hydrogen Production System which splits water into pure hydrogen and medical grade oxygen without the polymer membrane used in common electrolysers.

“This technology is ready to help transport networks and industries globally transition to hydrogen to help achieve zero-carbon targets,” says Christopher Boyle, managing director and co-founder of AFCryo.

“In New Zealand, an immediate opportunity is to turn the hydrogen refuelling network concept into reality with our technology for onsite and on-demand hydrogen production.”

Minister of Housing, Energy and Resources, and Research, Science and Innovation, Hon Dr Megan Woods, says this project is an exciting development.

“This is exactly the kind of collaboration that will start to unlock a new energy future for New Zealand as we seek to decarbonise our economy and have less reliance on fossil fuels.”

Taking green to another level

When it comes to greener construction, there are some Kiwi companies taking this to another level.

Take Natural Habitats Landscapes for example, wrapping facades of buildings with epiphytic and lithophyte plants to add living, breathing architectural function.

Two of the company’s green technologies include green walls and green roofs.

Acting as a “living skin”, these green oases have a number of benefits for both humans and the environment.

“By nature, plants are living filters, capturing and storing air pollutants as well as water pollutants,” says Graham Cleary, Natural Habitats founder.

“This makes them the ideal tool in the fight against climate change by their process of carbon sequestration and their ability to improve water quality.

“Plants also play an important role with their ability to mitigate stormwater runoff by absorbing excess water.”

The team at Natural Habitats design, install and maintain green roofs and green walls with “innovative, ultra-light technology, unlike any on the New Zealand market”.

“We do this with our bespoke Eco Pillow technology which primarily consists of recycled polystyrene that has been taken out of cities’ waste systems and then manipulated to mimic soil,” says Cleary.

Using polystyrene means the green roofs and walls are light in weight. This has a number of benefits.

“Although weight is often a primary concern of green roofs, Natural Habitats has devised the lightweight, Eco Pillow system which requires no extra structural changes and has the added benefit of being an ideal growing media for plants,” says Cleary.

The company has been able to get this media to around 20% of the weight of traditional media.

“To put that into context, if we’re installing a green roof on a building that, using traditional media, requires on tonne of media, you may have to spend an extra million dollars to ensure the structural integrity of said building.

“By replacing that one tonne with an alternative coming in at just 200kgs, then the additional cost is minimal, if not at all,” says Cleary.

The Eco Pillow technology also means the flora can be pre-planted in the nursery.

“The advantage of this is that it eliminates the possibility of failure of the plants as they are well rooted in the media within the Eco Pillow.”

This takes away the need to complete the planting on the roof, eliminating the possibility of a tool going through protective layers and damaging the waterproofing.

“Another advantage of our Eco Pillow system is its puzzle-like nature, allowing us to install green roofs and green walls systematically.

“This also means they can be removed or replaced individually without interfering with the rest of the wall or roof.”

Coming together

Construction has quite a significant impact on our environment, and NZGBC’s Andrew Eagles says that “if we want to leave a legacy for our tamariki and our mokopuna, we need to ratchet these down” to ensure a healthier future.

Sustainable building solutions are starting to become more accessible in New Zealand and by making these changes, it might just be possible for the sector to reduce its contribution to the country’s greenhouse gas emissions.

“It’s really rewarding to build buildings which are healthier and lower carbon,” says Eagles.

“It feels like you’ve had a bit of a challenge and then you achieve it – it’s a really great thing to be doing.

“And it’s going to take us all to get there.”