When it was completed in 1982, the William Clayton Building (now 133 Molesworth Street) in Wellington was the world’s first base-isolated office building. An upgrade has enhanced its earthquake resilience, and has some serious green credentials too.

Located on Wellington’s urban motorway is an engineering icon – 133 Molesworth Street. Its recent redevelopment enhanced the building’s earthquake resilience; reducing the impact of earthquakes and helping tenants get back to business as soon as possible after an earthquake.

The redevelopment also needed to deliver additional space, sustainability, and strong energy performance, while respecting the building’s original look.

It has. By adding two additional floors, the building doubled in size to 16,000m2. Sustainability was delivered through recycling the existing structure and original façade panels. Most of the building services were replaced with modern energy efficienct systems and, although the building has doubled in size, energy consumption has been reduced by a third when comparing the existing building performance.

The resilient building structure is base isolated and designed to remain largely undamaged, even during intense shaking. This was put to the test shortly after the completion of the redevelopment by the Kaikoura earthquake. The building successfully handled the full impact of the quake, meaning the tenant was back in the building the day after the quake – and the building was fully operational.

Despite a number of hurdles along the way (including the unexpected discovery of asbestos), the building was completed on time and to budget, thanks to close collaboration with the client, architect, and contractor. 


  • 2016 Concrete3 Sustainability Awards – Supreme Award Winner
  • 2017 NZIA Wellington Architecture Awards – Commercial Architecture
  • 2017 Property Council Awards - RCP Commercial Office Property Award, Excellence
  • 2017 Property Council Awards - Resene Green Building Property Award, Merit

Images by Jason Mann Photography


First of a new benchmark


Embodied energy saved


Structure, façade & systems

View from near the motorway
Highly visible central stair
Kitchenette and breakout space
Main entrance at night
View from near the motorway

Our team says

Great outcomes can be achieved when a team enjoys working collaboratively together. This is a project that makes me proud to be part of the industry.

Patrick Breen

Senior Technical Director – Buildings

Our client says

Key to the success of the project was the quality and approach of the team involved and how well they all worked together to bring the project through to a successful conclusion. They were proactive and coordinated from day one.

Mike McCombie

Director, Balanced Investments

Our People

Henry Tatham

Technical Director - Structural Engineering

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Patrick Breen

Senior Technical Director - Building Services

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