The Kanuka Premises
In what is thought to be one of the largest clear span buildings in the country, Garry Newton of Structural Concepts Ltd and Peter Roil of Kanuka Engineered Wood Products Ltd have collaborated to produce a feat of innovative engineering. They hope this will challenge the way those in the construction industry think about timber.
The result is the award winning processing factory for Kanuka. At 60 metres wide with no internal supports, this industrial masterpiece made primarily from laminated timber is a feat of innovative engineering, designed to showcase the same product manufactured within.
Owner and manufacturer Peter Roil required a building which could be designed, manufactured and built within a year. Therefore, the design needed to work in with the timber he could produce economically, over a six month time period. His brief to Structural Concepts specified a laminated timber structure with GL8 strength, a 60 metre clear span and a 6-metre stud height with an 11-metre apex. Also required was 90 millimetre wide timber using members as small as possible for ease of fabrication. It was imperative the timber be laminated, because it wouldn’t have been possible to achieve the dimension or the length required, using solid wood.
Integral to the design are the large roof trusses, which make up the majority of the 300 cubic metres of Pinus Radiata laminated wood used in the building. For added strength, the bottom chords of the trusses have been laminated with Douglas Fir. One of the many benefits of trusses is the ability to cover the required building width using smaller pieces of timber. In line with this need, the purlin span in the roof framing has been divided using an intermediate beam. The gravity load of the trusses has allowed for smaller columns, at a width of just 575 millimetres. Metal components in the shed have been kept to a minimum, with timber used for the framing and the majority of the bracing.
Garry Newton included many innovations such as the use of nails and cleats for every connection, except for the brace bays. The exclusion of bolts in favour of nails means less slippage and reduced costs.
Buildings like this are commonly constructed with steel. However with the benefits of laminated Pinus Radiata, it’s difficult to imagine why this is so. The use of timber has enabled every part of the process to remain within Hawke’s Bay, making it both cost effective and more sustainable. As well as being a renewable product, laminated timber has a greater fire resistance than steel, which tends to buckle in high temperatures. In comparison the beams simply char. Peter Roil hopes others in the construction industry will look to this design as a model for future buildings.
