A Future for Tall Buildings in New Zealand?

Take out #2: Addressing the carbon challenge

Given the conference was held against the backdrop of COP27, environmental sustainability was unsurprisingly front of mind.

Many presenters discussed how the southern hemisphere (particularly Asia, Africa and South America) will be the source of most new tall buildings worldwide over the next 30 years. Meanwhile, the northern hemisphere (predominantly North America and Europe) will need to focus on adaptive re-use and extending the life of its building stock to minimise the significant carbon impacts of construction.

"The construction and operation of tall buildings represents an estimated 40% of global carbon emissions and the superstructures of buildings contains approximately 50% of the embodied carbon" – facts acknowledged by almost every presenter.

Embodied carbon within a superstructure provides scope to rethink more traditional construction typologies. Both timber and modular construction opportunities present an obvious – yet only partial solution in some cases – and both typologies were considered extensively at the conference.

Aotearoa has many questions still left to consider:

• Should we investigate more steel recycling and the supply chain for other recycled materials?
• Ought more serious consideration be given to hybrid buildings such as concrete frames with cross-laminated timber infill floors?
• Can we explore less carbon-intensive materials?
• What can be standardised or labelled a 'kit of parts' with some controlled variation?
• What advanced manufacturing techniques could be employed?
• What new materials are being synthesised around the world?

A sustainable delivery strategy should be a fundamental consideration for every building venture in New Zealand, not just signature projects of excellence. We must take a broader view of sustainability than simply achieving a category within a rating tool.

Take out #3: The role of modular & digital

Construction efficiency remains a hot topic so it was encouraging to see some modular projects reaching new heights around the world.

Ten Degrees, a 44-storey, 546 multi-family unit building in South London, is currently the world's tallest. Completed last year, it has two in situ concrete lift cores. Its construction spanned 26 months, with 43 modules produced each week in a factory. But it will soon be outdone by a modular 58-storey tower, which is currently under construction.

In New Zealand we are constrained by a limited supply chain, cost of construction and seismic design issues. That said, significant efficiencies can also be realised by enabling a more proficient delivery strategy.

Investment in a considered digital execution plan at the outset of a project can enhance efficiency significantly. These shouldn't be confined to the design phase either; digital tools need to be defined for each phase throughout the project lifecycle. Projects need bespoke digital strategies that leverage the building information model. These strategies enable connection and collaboration for project stakeholders by feeding the data captured during construction and occupancy back into the digital twin to assist clients with future development decisions.

Consideration of WiredScore rating systems – "a global digital connectivity certification that evaluates, improves, benchmarks and promotes best-in-class connectivity in the built world" – also need to be embedded early within the establishment phase.