What happens when New Zealand companies with a passion for innovation team up? Big things.   

The Willesden Farms composting barn in the Banks Peninsula’s Kaituna Valley is a commercial-scale agricultural structure redefining what sustainable farm infrastructure can look like. 

Designed by NumatAgri and engineered in collaboration with DE Consulting & Engineers, the 185m x 31m barn forms part of a 300-hectare dairy conversion. The facility is capable of housing 500 cows over winter and feeding up to 1,000 – enhancing livestock management while significantly reducing the farm’s environmental footprint. 

To achieve the required clear spans and internal layout for the Willesden Farms barn, a total of 64 585mm x 135mm Prolam PL8 H3.2 Beams, measuring up to 16.2m long, were used as rafters spanning 12m with a 4m overhang. 

The scale demanded structural integrity, consistency and confidence in supply. Prolam delivered long, accurate lengths that met engineering requirements and streamlined installation. 

Why glulam made sense

For Wogan Hills and NumatAgri, sustainability was central to the brief. 

Timber offered strong environmental credentials compared to alternative materials, while also delivering practical benefits on site. The glulam structure feels warmer than steel – an important factor in livestock environments – and the H3.2 treated timber provides durability in the humid composting barn conditions. 

While not necessarily cheaper than steel upfront, the solution proved cost-competitive and efficient to construct and will deliver lower lifecycle and environmental costs long-term.  

According to NumatAgri’s Myles Stewart: “The builders really liked it – it’s easier to work with and was an absolute breeze to install”.

Prolam’s structural design expertise also helped shape the final structural approach, with the building design developed around the capabilities of the timber solution. 

Built for the future of farming

In an agricultural sector under increasing environmental scrutiny, projects like Willesden Farms demonstrate that large-scale dairy infrastructure can be designed with sustainability in mind. 

Strong, durable, thermally stable and engineered for longevity, the Prolam glulam solution contributes to a barn with a projected lifespan of 50+ years. 

Commercial scale, repeatable design

This was not a one-off building. The barn has been designed as a repeatable model for future NumatAgri projects – a scalable solution combining structural efficiency, animal welfare and environmental performance. 

“This eco-friendly alternative to steel-framed barns is up to 20% more cost-effective than traditional builds. We really like the timber construction. We think it’s a really strong design, a durable design, and one that works really well in the environment.”
-    Matt Iremonger, General Manager, Willesden Farms

Images and video courtesy of NumatAgri.