1. Construction Modularity: Cases from the UK Healthcare Sector
Dr Des Doran
Brunel Business School
Uxbridge
Middlesex
des.doran@brunel.ac.uk
Abstract
Purpose: The paper aims to examine the application of modular practices and principles in
the construction sector, an area currently underrepresented in the academic literature.
Design/methodology/approach: Case studies of three module manufacturers were
undertaken in 2009 using semi-structured interviews with key respondents. Interviews were
analysed and compared across a number of conceptual areas in order to provide cross-case
analysis
Findings: The findings suggest that whilst demand for modular building solutions is growing
there are a number of opportunities for the sector to provide modular solutions that can
compete more effectively with traditional, on-site solutions
Relevance/contribution: The paper articulates modular construction within the context of
existing concepts, principles and practices and demonstrates that construction modularity is
underrepresented amongst both the academic and practitioner communities.
Key words: Modularity, Construction, Product Architecture
Introduction
The primary aim of this paper is to explore the application of modular practices and
principles within the module construction sector, an area currently underrepresented in the
extant literature. In particular, the research aims to address the following research questions:
1. How is modularity defined within the construction sector?
2. How does „modular‟ construction differ from traditional non-modular construction?
3. What are the operational dimensions of construction modularity and do they differ
from the modular practices and procedures found in other sectors (e.g. automotive and
computing)?
The growth of modular production and modular development has gathered significant pace
during the last twenty years and seems set to dominate those sectors where product
complexity is high and consumer demands are constantly changing. The rate of such growth
can be attributed to a number of factors, including the potential for increased flexibility,
increased speed to market, reduced cost, the ability to configure new product variations
quickly and to accommodate the increasingly sophisticated demands of consumers in global
markets. Despite a plethora of research examining modularity in the automotive and
computing sectors, there has been very little research investigating the potential to apply the
same principles, practices and procedures within the multi-billion pound construction sector.
In 1998 a report examining the scope for improving the quality and efficiency of the UK
construction industry was published by Sir Robert Egan. The report – “Rethinking
Construction” urged the construction industry to improve performance through
standardization and off-site (Modular) production (OSP) and to mirror practices commonly

2. used within the automotive sector, particularly the application of lean processes and
procedures. OSP is defined here as the production of panelized and volumetric systems, and
major prefabricated components within a manufacturing environment. In essence, modular
buildings are constructed away from site (hence the term off-site production) and in a
controlled production environment. The completed modules are then transported to site and
positioned onto pre-prepared foundations.
Research by Goodier and Gibb (2007) indicated that the total value of the offsite market in
the UK in 2004 was €2.2bn. By far the largest value area of the off-site market related to non-
volumetric pre-assembly items (which includes cladding panels, building services, precast
concrete bridge sections. Non-volumetric items are all preassembled, but non-volumetric,
since they do not enclose usable space). The largest sector of the OSP market relates to new
builds, particularly hospitals, surgeries, nurseries and schools.
Pasquire & Connolly (2002) note that the benefits of modular construction can be categorised
as Off-site benefits (reduced labour, reduced waste, reduced storage requirements and
reduced welfare facilities provision), Programme benefits (including increased up-front
commitment (from manufacturers and suppliers), increased quality (due to factory quality
control systems), increased efficiency of installation (fewer installation processes) and
increased delivery reliability) and Manufacturing benefits (including improved working
conditions, improved productivity and improved performance (cost, quality, safety and
delivery). From an environmental perspective, Long (1999) found that modular solutions led
to a 30-60% reduction in time on-site, a reduction of 50% water quantity and material usage,
greater recycling activity, a reduction in CO2 emissions and the potential for reutilization and
reuse of prefabricated elements.
The demand for modular building solutions has gathered pace under the current United
Kingdom (UK) government which has allocated in excess of €2bn per year for the building of
new hospitals and surgeries. Aligned to this capital expansion hospital trusts are continually
seeking low cost and high quality buildings that address the specific needs of users and that
will continue to provide much needed capacity within an expanding and continually evolving
healthcare market. Unsurprisingly, it is this sector that has attracted increased interest of the
modular building industry as it seeks alternative markets in a sector that has been severely
affected by the current economic downturn. Despite the clear potential for the growth of
modular solutions a report commissioned by Constructing Excellence in 2004 concluded that
the growth of modular solutions has been limited. Similarly, Pan, Gibb and Dainty (2007)
observed that the barriers to the increased use of modular building solutions include
difficulties associated with complex interfacing between systems, the inability to unfreeze
design decisions, site access constraints and higher capital costs. In addition, there still exist
attitudinal barriers due to historic failures, the nature of the UK planning system and
manufacturing capacity.
Defining modularity within the construction sector
In order to make sense of what actually constitutes modular construction this research first
attempts to define construction modularity and then explores the characteristics associated
with modular construction. Instructive in this regard is the work of Langlois (2002:19) who
described modularity as “a very general set of principles for managing complexity. By
breaking up a complex system into discrete pieces – which can then communicate with one
another only through standardised interfaces within a standardised architecture.”

3. In a similar vein, Baldwin & Clark (1997: 84) define modularity as the process of “building a
complex product or process from smaller subsystems that can be designed independently yet
function together as a whole.” Modularity according to Schilling (2000: 312) is “a general
concept that describes the degree to which a system‟s components can be separated and
recombined, and it refers to the tightness of the coupling between components.” Cautiously,
Camuffo (2002:8) describes modularity as “… a vaguely defined and ambiguously used
term.”
Unlike the automotive and computer manufacturing industries there is no clear and distinct
definition of construction modularity. Instead, construction modularity is often described as
Off-site production (OSP) or Off-site manufacturing (OSM). Modular buildings can be
prefinished in the factory to include all fixtures and fittings, requiring a very limited amount
of installation work on site. Within the context of this research OSM and construction
modularity are used to represent the same activity and will be used interchangeably. In
essence, OSM involves the production of buildings within a manufacturing environment
which are then transported to site and placed upon pre-installed foundations.
Modular product architecture
Since modular construction is required to accommodate the varying and often sophisticated
demands of its healthcare clients it is important to understand the role that product
architecture plays in terms of satisfying and articulating such demands. Product architecture
has been described as “the scheme by which the function of the product is allocated to
physical components, that is, the arrangement of functional elements, the mapping from
functional elements to physical components, and the specification of the interfaces among
interacting physical components.” (Ulrich, 1995: 420) The author further states that the
scheme can be divided into three distinct elements:
(1) the arrangement of functional elements (the function of a product is what it does as
opposed to what the physical characteristics of the product are), (2) mapping from functional
elements to physical components (a component is defined as a separable physical part or sub-
assembly. Physical components implement the functional elements of the product), (3) the
specification of the interfaces between interacting physical components (an interface
specification defines the protocol for the primary interactions across the components
interfaces, and the mating geometry in cases where there is a geometric connection).
Exploring the nature of interface functionality, Sanchez (1997) noted that modular product
architecture is created when the interfaces between functional components are designed to
allow the mixing and matching of different components to rapidly configure product
variations. A desktop computer is cited as a familiar example of a modular product
architecture in which a range of parts can be combined to offer a vast number of product
variations without incurring those costs that traditionally accompany product variation and
flexibility.
Research approach
The research reported in this paper reflects an interpretivist approach since the topic of
construction modularity is complex and cannot be reduced to a series of law-like
generalisations. Such an epistemological position naturally lends itself to subjectivist
ontology since the goal of this research is to determine the application of modularity within
the construction sector and as such is exploratory in nature. The research strategy involves
case studies of three UK-based module manufacturers which accommodates cross-case
comparisons.

4. Data was systematically collected in each case study using site visits, interviews with
executives, in-depth analysis of company archival records, documents and observation
(Eisenhardt, 1989; Yin, 1994; Gill and Johnson, 1997). Formal collection procedures ensured
data quality and perceptual triangulation assured data validity. A case study database was
developed to facilitate cross-case analysis and explicit links were made between the questions
asked, data collected and the conclusions drawn to increase information reliability (Miles and
Huberman, 1994; Yin, 1994). The main data sources were interviews with key operational
respondents across the module supply chain that then led to extensive analysis of archival
records and documents. Interviews were semi-structured and explored the nature and scope of
modularity within the healthcare construction sector. Archival records and documents were
then used to test these opinions with quantitative and qualitative data
Case rationale and selection
The rationale for case selection was based upon the growth of modular activity within the UK
healthcare sector and the targeting of this market by module manufacturers keen to exploit a
market that requires speedy and often low cost solutions to very specific user needs and
requirements. The cases ranged from a full service design, build and install operation through
to a basic build and deliver operation thus providing the opportunity to compare and contrast
capabilities across the modular continuum. Each of the three case operations provided
modular solutions to the healthcare sector and viewed this sector as a target for strategic
growth. A summary of the case operations is provided table I.
Table I – Case details
Company Details Respondents
Company A Large company with fully Senior Operations Manager
integrated facilities, Senior Engineer
including R&D, design
services, frame manufacture,
fabrication facilities,
transportation, ground
preparation and assembly
Company B Small scale company with Senior Operations Manager
assembly facilities
Company C Medium sized company with Senior Operations Manager
assembly facilities Technical Engineer (HVAC
supplier for Company C)
Case study findings
Semi-structured interviews were conducted on-site with operations managers of each of the
case study manufacturers. Questions focussed upon defining modularity (essential for
understanding the essence of modularity within the construction sector), distinguishing
between modular and non-modular building solutions, the modular design process, the role of
the client in the modular procurement process and, finally, the limitations associated with
modular construction solutions.

5. Defining modularity
A number of questions were designed to assist the development and understanding of
modularity within the healthcare building sector. Such questions were designed to explore the
fundamental differences between modular and non-modular building solutions, the modular
design process, client involvement in the modular design process and the constraints
associated with the modular paradigm. The first question in this section required respondents
to define modularity within the context of their operations. In many ways responses to this
question in reflected the fact that the case operations had, on the whole, only operated as
modular operations and did not offer non-modular solutions.
The Company A respondent provided a simple but informed summation of building
modularity by noting that:
[Modularity] “is taking a number of processes and developing them into one module. The
concept is almost similar to creating „Lego‟ style modules that come together quickly to
deliver a building and its services.”
The Company B respondent provided a broader description/definition which articulated some
of the characteristics associated with building modularity:
For us [modularity] is quite a variable thing. We don‟t have a prescriptive fixed size, we have
preferred sizes which is a 3m wide module with 2.4m ceiling height, 6m long going up in 1m
increments upto 12m; that‟s our basic standard portfolio of module sizes. We also have special
sized modules which are used for a variety of service applications. They are what we would
like to build as they go through the factory with no real issue and no real redesign Then we get
the customer that comes along with a super job that we can‟t say no to and we will build
modules to any size as long as they fit on a lorry.
A more concise definition was provided by the Company C respondent who stated that:
“Modularity is offsite construction. It is completing as much of the building as possible in
sections that are transportable to site so that we can manage the amount of work that is done
on site so that we can control the environment and maintain quality.”
Distinguishing between modular and non-modular building solutions
In order to extend and inform the understanding of modularity within the building sector the
respondents were asked to describe how modular buildings compare to non-modular buildings.
This question was designed to seek a greater understanding of how modular building is
distinguished from traditional on-site construction and to gain insights into the characteristics
of modular buildings.
The Company A respondent provided a useful and informative distinction between modular
and non-modular solutions which focussed upon the perceived limitations of the modular
approach:
“There‟s going to be some restriction on dimensional attributes and layout given the way in
which the modules are manufactured. Transport is a key limiting factor.

6. The lightness of the structure is often seen as an Achilles heel in two main senses - one is the
feel of the building in terms of solidity, although we have started to improve that by offering
concrete floors that are poured here on site and transported. Secondly, the effects of summer
overheating which can be overcome with the right ventilation systems and the right use and
combination of materials.”
A second respondent from Company A focussed more upon the performance characteristics
associated with the modular approach:
First issue is speed. Modular buildings can be delivered up to 50-60% faster. You would
struggle to tell a modular building from a traditional build. The customer is getting all the
benefits of off-site construction, which is essentially cost, quality and speed. We work to the
same building regulations, HTM‟S [Health Technical Memorandum‟s] and insulation (Part
L2) requirements of a traditional build. What you are delivering with modular solutions is
certainty. In the last 5 years we have delivered 96% of our projects on time and 94% of our
projects to cost. Traditional build projects have an on-time completion rate of around 40%.
Modular causes minimum disruption of time and in some cases at a lower or equal cost.
Interestingly the Company B respondent providing a much briefer insight:
“There can be no difference. I‟ve worked on jobs where a multinational has worked on
buildings where part of the building has been built on site and another built off-site. The
customer has not known the difference. They would be visibly and serviceably identical.”
The Company C respondent tended to focus upon the benefits of the modular approach by
stating that:
“We don‟t have to contend with the elements outside. We don‟t have to contend with vast
changes in temperature which can create problems. This affects things like rendering; if
temperature is severe we can‟t render [whereas with a modular approach] we can maintain
output.”
The modular design process
In order to move beyond the basic elements of defining modularity and differentiating between
modular and non-modular construction the respondents were asked to discuss the steps
involved the modular design process. This line of enquiry was designed to gain an
understanding of how modular buildings are designed, procured, manufactured and installed –
in essence soliciting responses relating to the nature and scope of value creation activity within
this sector.
The Company A response reflects, to some degree, the completeness and extent of the
company‟s modular capabilities:
“Assuming that you have got the modular system in place then we have commercial project
teams which consist of multi-disciplinary people, architects, space planners, M&E staff,
manufacturing planning staff that will take a scheme from the client or can be done from
scratch. We will overlay the scheme with our modules in conjunction with our space planners.

7. The next stage is to transfer these details into the manufacturing system so that the parts can
be made and brought together.
The time to complete can be as little as 6-8 weeks. One of the reasons clients come to us is
because of the time it takes to complete a modular building, which is far shorter than a
traditional on-site build.”
Similarly, a second Company A respondent stated that:
Within a healthcare context, we will work with the architect, the client and other stakeholders
in order to arrive at a sensible and rational modular solution. In some circumstances where
the rationalization process suggests a traditional build solution we will not proceed on a
modular basis, due to the solution not being design effective. It is helpful to be involved from
an early stage so that we can provide suitable advice on the way in which modular solutions
can be applied to the project.
The Company A approach was, to a large degree, reflected in the description provided by the
Company C respondent:
“We tend to get a drawing from an architect with their impression of what they want. In the
case of healthcare projects this might include bathroom and en-suite provision, isolation units
with specific types of facilities, disabled provision with appropriate dimensions. The first thing
we do is take the drawing and we try to modularise it. By modularising we try and cut it up in
sections that suit the building layout and that can be transported.
Limitations of construction modularity
Whilst the limitations of modularity are well documented within the automotive and
computing sectors there is little or no research examining the constraints associated with the
provision of modular buildings for healthcare applications. In order to address this issue
respondents were asked to discuss the constraints/characteristics associated with the provision
and maintenance of modular healthcare solutions.
The Company A respondent focussed upon the dimensional transportation difficulties:
“Transport is the immovable object. There is an absolute size that you can transport. We are
limited by the 16ft 6in and obviously the width. When you get to 6m wide you need a lot of
additional provisions - Highways Agency involvement which is very complicated and
expensive. Weight is also an issue when providing more complex modules with M&E, concrete
floors etc which requires a fairly substantial crane to move the module around on site.
We spend more time considering the feel of the building, the acoustics, the thermal
management of the building, the cleanliness of the environment, the ease of cleaning surfaces.
Vibration is also an issue for modular healthcare buildings. We have to install thicker
concrete floors for some areas of a hospital, for example surgery rooms.
This view was extended by another Company A respondent:
“ Some of the key challenges we have are in terms of clear internal spaces. We have issues in
terms of our grid size and modular size when compared to on-site traditional solutions. What
we struggle with is high reception areas with the “wow” factor.”

8. The Company B respondent expressed similar views but returned to the issue of logistics
difficulties when describing the constraints of modularity:
“The things you can‟t do with modular are buildings with really high ceiling height and really
big spans. For example sports halls and supermarkets. Those types of buildings don‟t lend
themselves to three dimensional modular buildings. It doesn‟t mean to say that those types of
buildings can‟t have elements of offsite construction but this is not really a modular solution.
We can do about 3.3 heights, 16m on one horizontal dimension but it would have to have some
wind shear walls and cross-bracing.”
This view was echoed by the Company C respondent who returned to the issue of
transportation and the differences between off-site and on-site construction approaches:
“The modular constraint is what you can get down a British road or under a British bridge.
Off-site modular buildings are “signed off” straight away within the design process. This
means that decisions relating to wall colours, door types, floor finishes window sizes etc are
signed off at the start of the project rather than during say a 6-12 month period that is
standard for traditional on-site building projects; this necessitates a change of mindset
amongst architects, stakeholders and clients who may be used to making changes as a project
takes shape. Such changes are more difficult to accommodate with a modular build because
we start building the modules from the moment the contract is signed.”
Discussion
This paper has sought to articulate the dimensions of modularity within the construction sector
and in so doing contribute to the understanding of modular principles and practices within an
underrepresented area of modularity. The research was designed to explore how modularity is
defined within the sector, what constitutes construction modularity and how modular
principles are applied within the sector. Defining construction modularity elicited a number of
insightful, but essentially varied, responses which ranged from a series of processes, a variable
entity constrained by distinct size categories and offsite construction. These views are
summarised into the following definition of construction modularity: The provision of modular
solutions constructed off-site using modular principles and practices and delivered, installed
and commissioned on-site to a pre-determined modular plan.
Such a definition encompasses the key characteristics of modular construction and assists
understanding of the modular design process. A fundamental characteristic of the modular
design process is the need to overlay plans onto predetermined module templates in order to
arrive at the most optimal solution. In essence this is where compromise is reached and where
differences between off-site and modular solutions are most pronounced. Clients seeking
modular solutions have to accept the dimensional limitations that such solutions necessitate.
The research then explored what actually constitutes construction modularity and in so doing
set off-site modular production against traditional, on-site construction. The findings were
instructive. In terms of benefits, the key issues cited included the speed at which modular
buildings can be constructed, the certainty associated with delivery, less on site disruption and,
more recently, the potential for modular solutions that have visual as well as functional appeal.
The key negatives centred upon restrictions associated with dimensional attributes, constraints
associated with transportability (road widths and bridge heights), the lightness of the
structures, difficulties with climate control (overheating in summer and cold in winter) and
floor vibration issues (particularly evident in operating theatres where accuracy is of the
upmost importance).

9. An overriding theme of this research has been the issue of product architecture, manifest in the
shape, size, function and material construction of the modular buildings produced and
designed by each of the manufacturers that participated in this research.
The architecture of the modular buildings examined in this research can be articulated by
applying Ulrich‟s (1995) modular scheme:
1) The arrangement of functional elements. The function of a modular healthcare building is to
accommodate the provision of healthcare services. This can be divided into sub-functions
(consultation rooms, treatment areas, storage facilities, plant rooms and other patient related
services). The research has demonstrated that most modular buildings use extant procedures
and practices when considering functional elements
2) Mapping from functional elements to physical components. The functions described above
are manifest in HVAC modules (designed, manufactured and installed using modular
principles), shower modules (again, produced off-site and simply positioned within a module
framework and connected to services (electricity and water) and complete operating theatres
using standardised interfaces and other client specified modules (fully fitted and ready for use
operating theatres, staff welfare services, reception modules)
3) Interface connectivity specification. This element of the scheme relates to decisions
concerning how modules fit together, connect and communicate. In many ways one can see
that connectivity, (for example, to existing services (water, electricity, gas etc)) is standardised
and reflects industry and HTM specifications. The modules themselves are supplied to fit
together through the use of standardised bolting techniques.
Clearly modular building manufacturers exist to sell the modular concept and to take market
share from traditional on-site building solutions. To do this they need to continually strive to
offer products and services that can closely replicate on-site, often bespoke solutions, but in a
modular and cost effective manner. This is where the tension lies; how do you provide an on-
site solution to an off-site, modular build? The answer appears to lie in the development of
hybrid solutions that offer a more tailored modular approach whilst maintaining the modular
architecture, modular manufacture and modular build ethos that is so ingrained in the modular
build sector. At the moment the sector appears to work to standard sizes which are
accommodated by the modular building manufacturers. This often results in more rigid
product architecture and/or increased costs due to product waste and increased production time
(due to the need to cut down materials before installation).
In conclusion, the research presented above provides insights into the area of modular
construction, an area that is poorly represented in the extant literature and an area that has the
potential to provide an interesting addition to the field of modular enquiry. In this regard the
contribution to operations theory has been to define construction modularity, develop an
understanding of modular practices and principles and to highlight the application of
construction modularity using Ulrich‟s modular scheme. Whilst modular construction has a
number of inherent limitations but there exists a great deal of potential to substitute on-site
solutions if the product architecture and transport infrastructure issues can be dealt with in an
imaginative and sophisticated manner.

10. References
Baldwin, C & Clark, K. (1997), “Managing in an age of modularity.” Harvard Business
Review, Sept-Oct, pp. 84-93.
Camuffo, A. (2002), “Rolling out a World Car: globalization, outsourcing and modularity in
the auto industry”, IMVP Working paper, available at http://imvp.mit.edu/papers.
Constructing Excellence (2004), UK capacity in offsite manufacturing. A report published in
conjunction with the DTI and Imperial College, London
Egan, R (1998). Rethinking Construction, Construction Industry Board
Eisenhardt, K.M (1989), "Building Theories from Case Study Research," Academy of
Management Review (14:4), pp. 532-550.
Gill, J., Johnson, P (1997), Research Methods for Managers. Second Edition. London: Paul
Chapman Publishing
Goodier, C & Gibb, A. (2007). Future opportunities for offsite in the UK, Construction
Management and Economics, June, 25, pp. 585-595.
Langlois, R. (2002), “Modularity in technology and organization”, Journal of Economic
Behavior & Organization, Vol. 49, pp. 19-37.
Langlois, R and Robertson, L (1995).Firms Markets and Economic Change: A Dynamic
Theory of Business Institutions, Routledge, London.
Long, K. (1999). EU funds EuroHouse Research, Building Design, 1382, 12/02:5
Miles, M, Huberman, A (1994), Qualitative Data Analysis: An expanded sourcebook (2nd
edn.), Sage:London & Thousand Oaks, California
Pan, W., Gibb, A. G. F. and Dainty, A. R. J. (2007) Perspectives of housebuilders on the use of
offsite Modern Methods of Construction. Construction Management and Economics, 25(1-3),
183-94.
Pasquire, C & Connolly, G (2002). Leaner construction through off-site manufacturing,
Proceedings IGLC, Gramado, Brazil.
Sanchez, R. (1997). Preparing for an uncertain future: Managing Organizations for Strategic
Flexibility. International Studies of Management & Organization, 27 (2), 71-94.
Schilling, M (2000), Towards a general modular systems theory and its application to interfirm
product modularity, Academy of Management Review, Vol 25, No.2, pp 312-334
Ulrich, K. (1995), “The role of product architecture on the manufacturing firm”, Research
Policy, 24. pp. 419-440.
Voordijk, H, Meijboom, B de Haan, J (2006). Modularity in supply chains: a multiple case
study in the construction industry, International Journal of Operations & Production
Management, Vol. 26 No. 6, 2006, pp. 600-618.
Yin, R. K (1994), Case study research: Design and methods. Thousand Oaks, CA: Sage.