New Zealand Manufacturers of Prefabricated Buildings and Components 2017
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P. Rajagopalan and M.M Andamon (eds.), Engaging Architectural Science: Meeting the Challenges of Higher Density: 52nd 137 International Conference of the Architectural Science Association 2018, pp.137–144. ©2018, The Architectural Science Association and RMIT University, Australia. Prefabrication: New Zealand manufacturers of prefabricated buildings and components 2017 Milad Moradibistouni Victoria University of Wellington, Wellington, New Zealand [email protected] Brenda Vale Victoria University of Wellington, Wellington, New Zealand [email protected] Nigel Isaacs Victoria University of Wellington, Wellington, New Zealand [email protected] Abstract: The New Zealand population is growing fast. In 2017 it was 4,776,500 and has a 90% probability of increasing to 5.30–7.88 million by 2068. This raises the need for more houses that can be built easily, cheaply and fast and be aligned with the contemporary needs of the growing population. This paper focuses on prefabrication as a method of construction that can help the New Zealand housing industry to meet this growing need for more houses. This paper is part of a larger study investigating the use of prefabricated Accessory Dwelling Units (ADUs) as a potential solution to the shortage of housing in New Zealand. This paper reviews 182 manufacturers of prefabricated buildings and components throughout New Zealand to achieve a better understanding of the services they offer, product innovations, and limitations. All data is culled from manufacturers’ websites. An initial analysis reveals that prefabrication in New Zealand is currently focussed on components such as trusses and panels and not on whole buildings. The paper ends by considering what needs to happen if existing manufacturers involved in prefabrication have a role to play in meeting New Zealand’s housing needs. Keywords: Prefabrication; New Zealand population; housing shortage. 1. INTRODUCTION The New Zealand (NZ) population has increased significantly over the past fifty years and this trend is predicted to continue at least through the second half of this century. The population of approximately 4.8 million in 2017 is predicted to reach to 6.0 million by 2043, with 75% living in urban areas (MacPherson, 2016). As a result of this population growth, New Zealand is currently facing a shortage of 71,000 houses, increasing by 40 houses a day (Miller, 2017). Given the urgent need for more houses, it is important to uses the most efficient construction methods and housing types. This paper is concerned with the use of off-site site construction, but it is recognized that other approach could also play a role in providing additional housing e.g. increase densification through the use of high-rise buildings instead of single- story houses. If prefabrication is to play a greater role, then what prefabrication resources are currently available? This paper explores the current state of the prefabrication industry in New Zealand. This paper firstly defines prefabrication and briefly compares it to traditional methods of construction. It is worth noting that in 2013, 32% of new NZ houses incorporated some form of prefabrication (Moradibistouni and Gjerde, 2017). The paper then investigates the current status of manufacturers of prefabrication in different regions of New Zealand. The aim is to gain a better understanding of the current industry situation and opportunities for future investment and research. 2. PREFABRICATION Prefabrication is a method of construction where the elements of a building, ranging in scale from a component to a complete building, are manufactured at some distance from the final location. These elements are then purchased and carried to the final location where they are assembled and normally attached to pre-prepared foundations (Seratts, 2012, p. i). The history of prefabricated systems dates back to beginning of nomadic life. Ancient peoples who had to migrate, due to environmental conditions or external threats, needed houses that were easy, fast and cheap to assemble, disassemble and transport (Herbers, 2006, p. 14). Despite this early history and later milestones of prefabrication such as the firstiron-framed house built in England in 1830, the idea of manufacturing a house in a factory was only truly realised after WWII (Herbers, 2006, p. 14; Vale, 1995). In New Zealand, the first prefabricated house, pre-made in a builder’s yard, was imported in 1806 as a gift for Te Pahi, the Maori chief. By 1833 prefabricated house kit sets individuals were being imported into New Zealand (Vale, 2002). 138 M. Bistouni, B. Vale and N. Isaacs Figure 1: Different types of prefabrication. (Source: Moradibistouni and Gjerde, 2017) Prefabrication methods can be classified in different ways. In this paper, the five categories of component, panel, module, hybrid and complete building used (Figure 1) are based on Bell (2009). Given the construction industry is the fifth largest industry in New Zealand, the benefits of prefabrication could help the country meet the urgent need for more houses and respond to environmental and energy-related concerns (Moradibistouni and Gjerde, 2017). Table 1 summarizes the potential advantages of prefabrication in comparison with traditional building methods. Table 1 shows that prefabrication can potentially be faster, cleaner, and have fewer defects and unexpected accidents, while also using energy and water more efficiently. However, the industry could need more financial support to deal with the high capital cost of establishing factories. There may also be barriers for home owners to overcome, as there is an idea that prefabricated houses are temporary, low-quality buildings (Vale, 1995). The industry also needs appropriate Government support to ease the processes of manufacture, sales, transport, and final assembly or installation (Moradibistouni and Gjerde, 2017). As a first step, it seems important to study existing prefabrication manufacturers in order to understand their abilities and limitations. This could help the industry and government to see what they have and what they need for the future in order to achieve prefabrications’ true potential. Table 1: Advantages of prefabrication Advantages % Benefit Source Reduction in CO2 emissions 35% Gorgolewski, 2005, pp.125-126 Reduction in environmental impacts 30-70% Same as above More energy efficient 50-55% Britto, 2008, p.14; Bell, 2012, p.16 Less construction waste 40-90% Same as above More water efficient 30-50% Britto, 2008, pp.14; Phillipson, 2001, pp.3 Reduction in use of raw material 40-50% Phillipson, 2001, p.3; Gorgolewski, 2005, pp.125-126 Reduction of defects on completion 60% Same as above Growth in performance of materials and labour 50% Same as above Reduction in the energy consumption 50% Phillipson, 2001, p.3 Reduction in construction costs 15-30% Phillipson, 2001, p.3; Britto, 2008, pp.14 Reduction in construction time 35-57% Same as above Fewer total number of man-hours required 40% Stephen, 2012, p.16 3. METHODOLOGY In order to better understand prefabrication manufacture data on 182 manufacturers of different types of domestic scale prefabrication has been collected through a web-based search of manufacturers. The main source of names of companies involved in this sector was Prefab NZ (2018) a non-profit membership organization that informs, educates and advocates for innovation and excellence in offsite design and construction in New Zealand. From the Prefab NZ database, a list of 85 manufacturers of prefabricated buildings was compiled. A further 72 manufacturers of frames and trusses were taken from the Frame and Truss Manufacturers’ Association of New Zealand (FTAM NZ) (2016). Twenty-five other companies emerged as a result of a web-based search using keywords related to prefabrication. At the end of this process, 102 companies out of the 182 were selected based on relevance of their services to manufacturing a prefabricated domestic scale building. This list was later shortened to 51 companies that had the most conformity with the goals of the larger study, Prefabrication: New Zealand manufacturers of prefabricated buildings and components 2017 139 which is establishing whether there is a role for the prefabrication of Accessory Dwelling Units (ADUs) to provide affordable and livable houses for New Zealanders. ADUs are secondary residential unit providing the basic needs of dwellers, with no dependency to the primary unit (Smith, 2017). This process removed companies that did not have the specified criteria needed for the research, as explained below. • Include only companies directly manufacturing or building one or more types of prefabrication. This excluded companies who simply cut or shape elements (such as timber or steel) without factory assembly or those on-site builders with the ability of constructing a prefabricated home. • Exclude companies who produce general products for prefabricated buildings, as well as other type of buildings, or those who produce machines or software for prefabricated manufacturers. • Kitchen category only includes those companies who manufacture whole or some part of a kitchen (e.g. a sink fitted into a cabinet) and send to site it as a module. • Bathroom category only includes manufacturers that assemble the whole bathroom at their factory and send it to site as a module. After filtering manufacturers of prefabrication elements, the 51 which had the most conformity stayed in the list. Apart from type of prefabrication, there are various factors, such as additional services and guarantees, types of standard, and the level of flexibility offered to their customers that need to be investigated to gain a better understanding of manufacturers of prefabrication in New Zealand. Despite the importance of all these factors, in this paper only two factors (type of service and location of factories throughout New Zealand) are investigated due to their importance. The larger study, which is currently underway, will investigate all these factors. These were then classified into eight categories: component; panel; module; container; completed building; kitchen; bathroom; and other, based on the type of services provided for clients.