P. Rajagopalan and M.M Andamon (eds.), Engaging Architectural Science: Meeting the Challenges of Higher Density: 52nd 145 International Conference of the Architectural Science Association 2018, pp.145–152. ©2018, The Architectural Science Association and RMIT University, Australia. Learning from the past to build tomorrow: an overview of previous prefabrication schemes Milad Moradibistouni Victoria University of Wellington, Wellington, New Zealand [email protected] Nigel Isaacs Victoria University of Wellington, Wellington, New Zealand [email protected] Brenda Vale Victoria University of Wellington, Wellington, New Zealand [email protected] Abstract: The world population growth can potentially lead to a shortage of appropriate houses in many countries. It can also increase the cost of land, which will directly affect the price of houses. Given the advantages of prefabrication, this method has the potential to provide numbers of high-quality houses in a short time. However, despite many historic attempts to produce prefabricated houses, there have been many failures. This paper presents a review of previous house prefabrication schemes to better understand the factors involved in their failure. Prefabrication schemes in five different time periods have been reviewed. The review looks at the construction-related needs in each period, the way the method of prefabrication responded to those needs, and any weaknesses of the method. The review ends by suggesting the most important factor for the potential of prefabrication is the current negative perceptions of stakeholders, including house owners and financiers. These negative perceptions come from early prefabrication schemes which focused on quantity and speed over quality and aesthetic aspects, and the fact these schemes were often linked to shortages of conventional building materials. Keywords: Prefabrication; housing; housing shortages; material shortages 1. INTRODUCTION A building can be constructed using different methods and materials. Choosing the best amongst the various options is affected by factors such as availability, cost, and location of site. As an example, in most vernacular architecture indigenous materials are used as these are cheap, readily available, and have the most conformity with climate (AIA, 1976). Despite the effect of materials and climate on the choice of construction method, it is also affected by needs and aims of the building. For example, the choice might be different if the aim is to create an energy-efficient or zero energy building, or where time is the main constraint and the building has to be ready as quickly as possible. This paper has studied the construction-related needs of societies in five different time periods and the way prefabrication responded to those needs. It has also looked at any successes of the industry and investigated the reasons behind any failures to see what factors need to be considered to ensure the success any future prefabrication venture. This paper is mainly shaped around the history of prefabrication in UK, United States of America and New Zealand while also noting important examples from other countries.The first step in this analysis is to define prefabrication and its different types. 2. PREFABRICATION Prefabrication is often regarded as synonymous with standardisation. Le Corbusier compared the process of building a house with a car production line and believed that the construction industry could be streamlined if the process of building a house became more like that of making a car, thus moving production from the site to the factory (Vale, 1995, p. 64). Prefabrication has come to mean a method of construction whereby building elements, ranging in size from a single component to a complete building are manufactured at a distance from the final building location. These elements are then sold and carried to the final location, usually by motor vehicles, where they are assembled and attached topre-made foundation (Seratts, 2012, p. i). These can be classified based on the materials and systems used or the degree of prefabrication Moradibistouni( and Gjerde, 2017). Based on the degree of prefabrication five groups emerge (Figure 1). 146 M. Bistouni, N. Isaacs and B. Vale • Component: this group comprises simple pre-cut and pre-shaped elements, and the more complicated sub- assemblies, made by combining more than one element (Bell, 2009). This group has the least degree of prefabrication but has more flexibility in terms of the final house. It usually needs more onsite work with more potential for defects (Boafo, 2016). • Panel: panels are two-dimensional elements made up of a limited number of components, joined together in the factory. Panels are easy to transport using a flat back trailer and offer a high level of flexibility with less on-site work compared with components. Panels can be simple pieces which need more on-site work or made in more complete forms that include cladding, doors, windows and even wiring and plumbing (Bell, 2009; Elitzer, 2015). • Module: modules are three-dimensional units made up of panels joined together in the factory. Modules, which are approximately 80-95% completed before leaving the factory, are very useful for buildings with a repetitive geometry (Boafo, 2016). • Hybrid prefabrication: a combination of the modular system, usually for service zones, and the panelised system, for the building envelope. This combination makes transportation easier while decreasing the possibility of defects as the complex service zone is factory made (BRANZ, 2013). • Complete Building: the entire building is factory constructed and moved by a heavy haulage vehicle to the site, where it is attached to the permanent foundations (Steinhardt, 2013). Figure 1: Different types of prefabrication. (Source: Moradibistouni and Gjerde, 2017) 3. METHODOLOGY This paper is part of a larger study investigating the potential use of prefabricated Accessory Dwelling Unit (ADU) as a potential solution to the shortage of housing in New Zealand. An ADU is a secondary residential unit providing the basic needs of dwellers, with no dependency to the primary unit (Smith, 2017). This paper is a literature-based investigation that explores the potential for prefabrication to act as a resource-efficient method of construction by looking at what has succeeded and failed in the past. This paper explores the history of prefabrication in five different historical periods: before WW I; during both World Wars; between the two World Wars; after WWII; and the present time. The scope is limited by only considering prefabrication related to housing. The similarities of this effect in both World Wars means that here they are treated together. The paper discusses how prefabrication helped the construction industry in the selected countries to meet market needs by exploring the potential benefits and weaknesses of the prefabrication method used during those periods. In doing this it focuses on the reasons behind failures to see what can be learned from them. In each period the reason prefabrication was chosen as method of construction is outlined and the ability of this method to respond to those needs is investigated. 4. PREFABRICATION BEFORE WW I (BEFORE 1914) The history of prefabrication dates back to the beginning of nomadic life and times when people had to migrate due to external threats or environmental conditions. The main reason people looked to prefabrication was their need to have houses which were easy to assemble, disassemble, and transport (Herbers, 2004, p. 14). These early prefabricated shelters were made of some pre-cut structural elements, usually timber, joined together using precut holes and/or ropes and covered by an envelope of leather, woollen fabric or other natural materials. Examples of these shelters can be found in the civilization of the early Persians, North American Indians and Mongolians, respectively called Black Tent, Tipi and Yurts. Other examples can be found in different ancient nations (Giller, 2012). Learning from the past to build tomorrow: an overview of previous prefabrication schemes 147 In the same way emigration to British colonies in the 18th and 19th centuries, led to the development of transportable prefabricated houses and housing components. The reason behind these prefabricated buildings was again the need for houses which could be easily transported and assembled, often on an unknown site. Most of these houses were made of timber and were covered by canvas and later clad with weatherboarding (Smith, 2009). These houses could even be assembled by unskilled owners. Once the immediate need for housing was satisfied and sufficient building skills accrued in the new colonies, the need to ship prefabricated houses was less urgent. One result of this is that little can be learned about failures as firms just disappeared. 5. PREFABRICATION DURING THE WORLD WARS (1914-1918 AND 1939-1945) During both World Wars, most factories changed their function to serve the war effort. In the UK, and other countries, the draft reduced the availability of men to operate factories or build, leading to a significant shortage of houses, while the focus on the manufacture of war goods led to a shortage of building materials (English Heritage, 2011). Particularly in WWII, there was a need for methods of construction with less on-site work which used materials more efficiently (Harrison, 1945). This gave a spur to prefabrication as this method was potentially able to reduce use of raw material by 40-50% and construction time by 35-57% (Phillipson, 2001, p. 3; Gorgolewski, 2005, pp. 125-126; Britto, 2008, p. 14). One of the most prominent prefabricated structures built during WWI was the Nissen hut, designed by Canadian engineer Peter Nissen, as a cheap, portable shelter for the British Army. The building, which was made of corrugated sheet metal pulled into a half cylinder and fixed on brick foundations, could be used for different functions such as a shelter, hospital, or armoury (Florian, 2013; Decker, 2005, pp. 5-7). The Nissen hut has been claimed as the first mass-produced prefabricated building (Mallory, 1973.