It’s been 15 years since Ben Exton was a student, digging silt and liquefaction from people’s homes.
The memory of digging silt from his great uncle’s house and his great uncle breaking down in tears still sticks with him.
The Canterbury earthquakes happened during Exton’s formative years, leading him to become a structural engineer. It’s influenced his career trajectory so much so that along with Geoff Banks, a practicing structural engineer during the Canterbury earthquakes, they set up a company called Seismic Shift.
Seismic Shift aims to deliver affordable resilience to earthquake-prone communities. One of the products they’ve created is FrontFoot – a 12 kilogram metal disc that has upwards of 80 components.
So how does it work?
Exton says there’s a series of small concrete pads that are about half a metre in each direction and those are located at each of the locations of their devices which is spread across the floor plate.
Seismic Shift chief executive Ben Exton says when it comes to cost, the percentage of the building costs that you’re adding onto is around 3% and at high volume, this would be down to 1.5%. Image source: Supplied remark.nz
A layer of special material goes over the top of those and then a concrete slab is carved over the top – just like a conventional house slab, he says. The devices fit into the slab on the top.
“They allow that slab to move relative to the ground and those isolated beds are effectively moving separately – they move with the ground so they move separately to the house,” Exton says.
“It’s that movement that’s really key because when we allow something to move a little bit it generates some friction and that reduces the force, accelerations, displacement within the movement within the house above, so really if we dampen what the earth’s doing then the house is going to be better off.”
The 31-year-old says you can think about it like the shock absorbers in your car.
“What it’s designed to do is to allow the house to slide relative to the ground and when it slides, it absorbs energy and as it moves away from its neutral position, it builds up a restoring force which pushes the house back to its original position.”
“It’s really important because you need a house to be reset, ready for aftershocks,” Exton says.
The device is designed to be good for 50 years minimum with no maintenance – but the caveat is if there is a level of shaking beyond code level, then there is a requirement to inspect them.
Exton says when it comes to cost, the percentage of the building costs that you’re adding in is around 3% and at high volume, this would be down to 1.5%.
“We’re dealing with a building system that’s been going for a long time – you don’t want to have too many changes required. Also from a consenting perspective, we need to keep it as consistent with typical practice as possible.”
Seismic Shift chief executive Ben Exton. Image source: Supplied remark.nz
The general rule of thumb, Exton says, was about one FrontFoot device per 10 square metres but this would vary depending on where you were in the country and how heavy the house was.
Just last Friday they did their first installation of the devices in a 240 square metre home that is being built in Central Otago. The house had 23 FrontFoot devices installed.
So, why a focus on new builds? Exton says retrofitting would cost a lot more and there would be a lot of unknowns.
“How was the house actually built back in the 1930s or ‘40s? And what condition is it still in now?”
The overall philosophy, Exton says, is that with time, resilience will be built up in the building stock of New Zealand.
“So, as older homes are replaced with newer homes, the overall level of resilience increases across the country.”
Natural disasters and insurance
Insurance is a contentious topic in New Zealand – with a report published last week from advocacy organisation Consumer NZ highlighting several problems.
These problems include the rising costs of insurance and a growing number of New Zealanders ditching insurance because of the cost.
Academics told Consumer NZ the country has until 2040 before we start to see some insurers exiting Aotearoa. They also suggested some of the country’s main centres could see insurance retreat by the end of the decade.
Alongside this, insurance comparison website Quashed reported last week that the average New Zealand household with a car, contents and home insurance policy could now expect to pay over $5000 a year on their premiums.
With a spotlight on house insurance and insurers moving towards risk-based pricing, this was all flowing through, Quashed’s chief executive Justin Lim said.
Exton says as people start to potentially see insurance withdrawal, this type of technology will allow them to take some control into their own hands.
“It’s very similar in Japan – they’re probably a wee bit further down the road than we are,” he says.
In Japan, the amount insured under earthquake insurance is between 30% to 50% of the coverage amount of someone’s fire insurance.
“Homeowners there are quite motivated to do something about it because they wear that risk personally. And so over there, if your house meets certain levels of performance, you can get insurance discounts.”
Exton says it’s encouraging to see other countries implementing insurance discounts for people who do more than the minimum.
Consumer NZ’s report also mentioned the lack of discounts New Zealand consumers receive when it comes to insurance, noting that many insurers had stopped multi-policy discounts.
And questions remain over who will pay for the country’s adaptation measures when it comes to climate change and natural hazard events.
Research from Consumer NZ found there was clear sentiment from people that the costs need to be shared between all parties – insurers, central and local government, and property owners.
A barrier
Exton says while there’s a lot of worry about insurer withdrawal and calls for people to develop solutions that’ll help, “we find a real barrier to Kiwis being willing to actually front up and pay for it”.
The majority of the feedback they’ve had is that people would rather put money into having a nicer kitchen, or that their build costs were already so high it was hard for them to justify stretching an already stretched budget.
“Part of that is it’s something that sits in your house that you hope you’ll never need. It’s something which you’re not seeing the benefit of every day like a kitchen … it’s that mentality we really battle with,” Exton says.
Exton says while these types of technologies won’t be a substitute for insurance, they could be items that can maintain insurance “when it’s otherwise decaying”.
“It’s getting ahead of things …These technologies go hand in hand with insurance.”
Calling on the wider population
In the short term, Seismic Shift will be focusing its efforts not only on New Zealand but offshore in places like Japan, the USA, Canada and Chile.
They also have another product called Quake Defender which is more focused on commercial buildings.
Quake Defender uses friction to dissipate energy and can be installed in building walls.
“It means that what the building is feeling is lower than what the ground is dishing out.”
This can be used in commercial buildings and enables people to put solar panels onto the roof of buildings, he says.
“That additional weight would normally make them more vulnerable to earthquakes, and by putting our device into the buildings, we can enable the buildings to take that extra weight and perform better.”
“In those situations where a building owner is getting additional revenue off, say solar panels that they’re then able to install, and their building value is increasing because of that revenue by more than the cost of our system – that’s when people are quite motivated,” Exton says.
Exton says there’s a lot of fantastic work going on technically but he does call on the wider population to think more carefully.
“If we don’t like the fact that insurance is becoming more expensive and insurers are starting to walk away, then what are we going to do about it? Are we actually willing to pay a little more to have better performing houses or are we going to complain on both sides?”