New Zealand must reform building codes and learn from Europe and the United States, which are now leading the way in building mid-rise and high-rise buildings out of wood. That is according to Nate Helbach, founder and CEO of Neutral – the developer behind Ascent and The Edison – a 31-storey timber-and-concrete skyscraper that broke ground in Milwaukee last week, who said there are no limits to timber skyscrapers.
“We build exclusively with mass timber in Milwaukee, Madison and San Francisco (in the United States) as our primary structure,” Helbach told Radio New Zealand on Wednesday, adding that Neutral, now on its third building, “chooses mass timber as its primary structure because it’s carbon neutral.”
Helbach, who is in New Zealand to speak at the New Zealand Institute of Building conference, said wood “gives you this beautiful biophilic environment, (which is) perfect for residential and for-rent buildings,” achieving rental rates that exceed the 2-3% premium for high-rise and 5% for low-rise construction.
And then there is fire protection, with Helbach revealing that rise testing is proving that mass timber is safer to use in high-rise buildings: “The reason for this is a process known as charring, which means that wood burns at a constant rate, even more so than steel-and-concrete,” he said.
“So if a mass timber building ever burnt, it would burn at a very constant rate that is highly predictable – which is much safer for fire and safety personnel than a steel-and-concrete building.”
Nate Helbach, founder and CEO of Neutral – the developer behind Ascent and The Edison – on RNZ on Wednesday.
Using the International Building Code, the US also has different fire ratings for building types: “So the jurisdiction in Milwaukee, Wisconsin has allowed us to prove equivalency to steel-and-concrete…That means that (for The Edison) we need a three-hour column-and-beam that essentially lasts three hours so fire and safety folks can evacuate the building.”
When it comes to building taller buildings out of wood, “the only thing you will need to do is add additional fibre to the timber – as sacrificial layers in case the fire burns through the timber to load the building – so if you want to go higher you can, but what that means is that your structural load will increase which your beams get larger.”
Using BIM to design buildings, Helbach said the mass timber if fabricated in a factory using precision construction: “With concrete, you are pouring on site, with lots of defects and mishaps, whilst with mass timber we drill down to every penetration and able to predrill all holes in a factory.”
Addressing one of its biggest concerns, moisture mitigation and water damage is probably the biggest concern for insurance companies: “With wood, it does rot; it can get a lot of moulds – dry rot and wet rot. But this does require extensive planning and testing both during the construction process and after it.”
The push to use wood in more projects comes after building commissioners in Auckland yesterday declined consent for a 10-11-storey mass timber office block – covered by Wood Central last year – due to its scale and impact on the area.
- To learn more, click here for RNZ’s interview with Nate Helbach, the founder and CEO of the development firm Neutral.
