**1. Introduction**

Since the housing crisis of 2008, the delays in housing starts and completions has resulted in a widespread housing shortfall in the UK that has challenged policymakers and developers to re-evaluate their position on modern methods, acceleration techniques, and technological opportunities [1]. Whilst traditional construction continues to serve as the primary mode of new housing fulfilment, recent evidence suggests that in order to meet the future needs of UK households and fulfil a more diversified spectrum of housing solutions, modern methods, and offsite techniques are of critical importance [2,3].

Alternative methods to traditional construction are increasingly being explored as a way to address the housing crisis in England. This is demonstrated by the recent parliamentary inquiry into MMC and Homes England's Strategic Plan in which developers receiving funding for developments of over 50 units must incorporate some form of MMC [4,5]. In England, up to 340,000 houses are needed per year to meet housing demand [6], however, only 164,390 new homes were completed in the England during 2018 [7]. Of these, approximately 17% were completed by HAs and less than 2% by local authorities, showing HAs is crucial in the delivery of affordable housing [8]. With 145,000 affordable properties required in England per year [6], based on recent performance, HA development will be critical to achieve the required output.

As a central agency responsible for providing adequate and quality housing to residents throughout a given region, UK housing associations (HAs) are defined as 'not-forprofit social landlords that provide homes and support for around 6 million people all around England' [9]. With pressure to accelerate the rate of delivery for such social housing

**Citation:** Agapiou, A. Barriers to Offsite Construction Adoption: A Quantitative Study among Housing Associations in England. *Buildings* **2022**, *12*, 283. https://doi.org/ 10.3390/buildings12030283

Academic Editors: Pierfrancesco De Paola, Francesco Tajani, Marco Locurcio and Felicia Di Liddo

Received: 20 January 2022 Accepted: 28 February 2022 Published: 2 March 2022

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**Copyright:** © 2022 by the author. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

solutions that are affordable and high-quality, the viability of offsite manufacturing is a pragmatic consideration that must be weighed, assessed, and considered for meeting future needs. Whilst a growing body of literature has critically explored the advantages and potential limitations of prefabricated, modular, and offsite construction practices, the lack of consensus and dependency upon traditional methods of construction have led to conceptual and ideological gaps that are continuing to threaten the long-term viability of this modern solution.

The extant research has largely focused on the experiences of the housing sector at large towards offsite construction, particularly private housebuilders. Currently, there is a dearth of research into the potential for adopting offsite solutions within HA developments, notwithstanding the 2017 report published by the University of the West of England which assessed the evidence for the take-up of prefabrication in the social housing sector in England [9]. For HAs, organizations that are confronted with a need to accelerate the rate of construction and mitigate the longstanding reputational threats of low-quality, low-efficiency housing, the practical opportunities of offsite housing are significant.

There is a growing interest in OSC from HAs, demonstrated by investment in their own manufacturing facilities [10,11] and research projects, such as Gateshead Innovation Village (Home Group 2019). Of the top 50 biggest developing HAs, 23 expect to complete homes using MMC in 2019/20, an increase from 16 in 2018/19 [12,13]. Despite this, OSC uptake nationally for HAs is low. If uptake is to increase, the perceptions of HAs towards OSC need to be understood, including the perceived barriers to OSC adoption. Currently, there is no literature focusing on these perceptions; a gap that this research begins to address.

Therefore, the aim of this research is to explore the perceived barriers within housing associations towards the use of OSC and how these compare with the perceptions within the wider housing sector. The objectives of the study are three-fold: (i) to critically review perceived barriers for OSC in the housing sector; (ii) to identify perceived barriers among HAs in using OSC methods and how these compare with the perceptions of the wider housing sector; and (iii) to explore whether experience in OSC methods affects perception of OSC usage.

#### **2. Housing Associations and Offsite Housing**

Despite an increasingly robust history in UK housing deliveries, offsite construction is often confronted with industry resistance, particularly in public housing sectors where governmen<sup>t</sup> officials are challenged to justify value for money. Rowley et al. [14], for example, have observed that the delivery of affordable social housing by governmen<sup>t</sup> agencies is threatened by a variety of concerns, including changing housing prices, economic conditions, demand-side variables (e.g., employment, wage growth, investment yields) and supply-side variables (e.g., land supply, construction efficiency, labour costs, planning regulations). The resultant bullwhip effect in housing supply, a phenomenon initially observed by Wheaton [15] in relation to private sector housing fulfilment, results in an over-under supply model that, whilst progressing towards natural equilibrium, is at risk for cyclical changes and delays. Therefore, MacAskill et al. [16] argue that where the primary 'goal of affordable housing is to achieve equilibrium', thereby eliminating the need for a waiting list or stricter qualifications, gap mitigation strategies (e.g., housing transfer, expedited construction methods) are needed to overcome systemic gaps in the housing supply. Central to the primary economic advantages of offsite housing identified by the NAO [17] is the volumetric housing benefits that provide housing associations with distinct advantages, including earlier rent recovery, a shorter borrowing period, less project delays, and less on-site inspections. Forecasting upwards of 80% fewer project defects and upwards of 80% compression of the time of delivery, the findings presented by Miles and Whitehouse [18] also confirmed a direct benefit to the housebuilder and a significant, broader social impact due to the accelerated delivery of high-quality, often affordable housing solutions. As developers weigh the functional and systemic advantages of offsite construction, Barton et al. [19] confirm that higher quality, higher efficiency prefabrication

will not only reduce the operational costs and emissions of the property over time, but will prescribe a future structural standard that dramatically improves the broader standard of practice in the construction industry.

#### *2.1. Literature Review*

A cursory review of the offsite construction literature reveals a dearth of academic research into the perceptions of HAs specifically towards OSC. Only Kempton and Syms [20,21] have explored this, focusing on the perceived impact on maintenance and asset management. To address the first objective, the literature focusing on perceptions towards OSC within the housing sector was identified and reviewed. Literature was obtained through searches on online databases, including Google Scholar, ARCOM, Science Direct and Ingenta Connect. Terms, such as "offsite construction", "off-site manufacture", "prefabrication", "modern methods of construction" were used in conjunction with "housing association", "housing" and "residential". For brevity, only UK based or UK concerned literature was included for detailed examination. The literature search was expanded through snowballing; reviewing the citations and reference list of each paper and further literature in which the original paper has been cited [22]. The literature predominantly consisted of journal articles, conference papers, and industry generated reports. Abstracts and executive summaries were read to ascertain whether the literature contained research into perceptions. Those that did were thoroughly examined to establish the perceived barriers to OSC use, in order to address the first research objective.

The literature contained a larger range of perceived barriers within the wider housing industry, with 24 themes identified. Figure 1 illustrates that the results were multimodal with four barrier themes, each featured in 53% of the literature reviewed: industry perceptions, customer perceptions, skills requirements, and cost.

**Figure 1.** The number of pieces of literature on each barrier theme is featured within the literature.

The section below discusses the level of importance attributed to these four key barrier themes, with comparisons made between their significance within the wider OSC housebuilding literature and studies related to housing association perceptions. A critique

of the wider body of knowledge is also provided, highlighting both methodological gaps and weaknesses within the OSC housebuilding literature, and how this may limit the scope of direct comparison with the research findings. The theoretical gap is then defined as the basis for further consideration and exploration.

#### 2.1.1. Industry Perceptions

The attitudes of the housing building industry towards OSC are a frequently occurring barrier; however, it is not considered to be highly significant, ranking sixth out of seven most important barriers to the use of prefabrication [23]. In Pan et al. [24,25], "Attitudinal barriers due to historic failures" was selected by 11% of participants as being one of the three most significant barriers to the use of offsite-MMC. This is supported by [20,21,26], who identify that previous negative experience with non-traditional construction methods has fueled tarnished perceptions and negative attitudes towards OSC. The perceived risk of adopting new processes and systems was a highly ranked constraint in [27], selected by 24% of participants. In Pan et al. [24,25], "Reluctance to innovation" was selected by 11% of participants as being one of the three most significant barriers to using modern methods of construction. Conversely, "Want to modernise" was presented as a driver for investing in MMC in [28] and selected by 39% as a driver. However, [28] reveal that the majority of housebuilders and HAs considered themselves "Followers" or "Late adopters" to MMC. Only 3% of HA participants consider their organisation to be "Market leaders" [29].

#### 2.1.2. Customer Perceptions and Attitudes

Public attitude is also considered an important barrier to prefabrication uptake by housebuilders [23], supported by [27], where it ranks as the joint fourth biggest constraint. "Buyer reactions" is also the third most selected main barrier to modular construction [29]. This is supported by [20,21,29], who identify that previous negative experience with nontraditional construction methods has fuelled tarnished perceptions and negative attitudes towards offsite construction methods. However, "Culture resistance-poor public perception" is a lowly ranked barrier in [30], jointly ranked 17th in significance out of 20 perceived barriers. "No demand for prefabrication" is the lowest-ranked barrier affecting prefabrication uptake in [31].

#### 2.1.3. Skills Requirements

The need to address skills shortage is frequently cited as a significant perceived barrier to the wider take-up of OSC. For example, 87% of participants in [31] considered this to be a significant barrier, making it the second highest selected barrier. It was also considered significant by participants in [29], where it was the fourth most selected main barrier to modular construction.

Dave et al. [27] highlighted the perceived concerns over the lack of training and experience of builders, contractors, developers, and designers, including architects and engineers. However, skills requirements are not a significant perceived barrier according to [28], in which only 6% of participants considered it to be a barrier to MMC uptake by developers. This is supported by [24,25], in which only 11% of participants selected "Skills shortage" within the top three barriers to offsite-MMC, and [23] where it is considered the least important out of the seven presented barriers for prefabrication.
