An opportunity and a warning: Architects take stock of Wellington's risky buildings

Wellington City. Photo / Mark Mitchell

Wellington's earthquake-prone buildings are more commonly thought of as being a headache, but architects say they can be an opportunity too.

Architects have also warned commercial property owners not to opt for the bare minimum when it comes to New Building Standard (NBS) ratings, because the legislative goal posts will likely shift in the future.

This year several office blocks across the city have been abruptly vacated due to new engineering assessments returning lower than expected NBS ratings.

Designgroup Stapleton Elliot director Emma Macann said the standard for tenancies was growing every year, which was largely being driven by government departments.

They were requiring higher-performing buildings and higher sustainability ratings, she said.

In other words, the market is going above and beyond the regulatory requirement to strengthen buildings to at least 34 per cent NBS.

Macann warned any changes to the building standard in the future would be reflected in NBS ratings.

"So if you have a 80 per cent NBS building, that might drop over the years. Do what you can feasibly do and don't go for the bare minimum."

She also described much of the capital's building stock as "tired".

"So while seismic strengthening is a costly and long process, often it also gives us great opportunity."

This could range from upgrading services so they use less energy, improving the façade for better insulation, and upgrading interiors to entice people back to office life.

Macann spoke yesterday in a panel discussion as part of JLL's Future of Real Estate conference.

Global leaders from across the commercial property spectrum put a spotlight on how the industry is adapting to economic and geopolitical turbulence, and increasingly urgent social and environmental imperatives.

Ministry of Education staff recently vacated their building due to seismic concerns. Photo / Mark Mitchell

Architecture Plus director Belinda Tuohy agreed with Macann that strengthening presented an opportunity to add more value to a building than just improving the actual structure.

"It's such invasive work. You're doing so much to the building anyway, it's a great opportunity to get in there and correct other issues and give the building a life for another 50 years or more."

Tuohy said there has been a recent changing trend in workplace design, including a greater focus on wellbeing.

She said natural light with good views was important as well as ventilation and temperature control.

"So people are getting oxygen and fresh air, so you don't fall asleep in the middle of the day."

Some offices were even going as far as including sleep pods in their layout, she said.

Buildings could also be made more efficient like a heritage project Tuohy worked on in Lower Hutt.

The strengthening solution was deep piling up to 25m into the ground.

Coils of water pipes were inserted into the piles and returned back up to the mechanical system.

Tuhoy said this allowed for the natural temperature of the earth to be used to reduce the need for as much cooling and heating.

On NBS ratings, Tuohy said better communication was needed around risk profile.

She said an NBS rating was only as good as the weakest part of a building, which could range from beams and columns holding it up to non-structural elements like a brick on the façade .

"So the actual risk to the building owner and the occupants will vary greatly.

"It's not just a number, so you need to have somebody explain to you what is it that's driving the actual NBS of that particular building.

"Is it a quick fix? Is it something that's easy? Or is it something that's more endemic through the whole building and would require a lot more intervention?"