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File: Building Pdf 84170 | Unlocking The Potential Of Modular Construction Building Final By Anilea
economics analysis facts forecast construction methods modular modular construction is touted as the future of the building industry but while the sector is rapidly growing in some areas there are ...

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           ECONOMICS
           analysis / facts / forecast
           CONSTRUCTION METHODS MODULAR
           Modular construction is touted as the future of the building industry, but while the sector is rapidly growing  
           in some areas, there are still obstacles to overcome. Alex Hyams of Alinea, Ed McCann of Expedition 
           Engineering and Hugh Ferguson assess the pros and cons of volumetric modular offsite construction
           01 / INTRODUCTION
           Is modular construction the future           shows the way technology is                 Figure 1: Gartner hype cycle, showing a technology’s journey to 
           for the UK building industry as its          adopted, with the “peak of inflated         mainstream acceptance
           supporters have long maintained,             expectations” followed by the 
           or is it a hopeless effort to translate      “trough of disillusionment” (see 
           factory techniques into an                   figure 1). The 2016 Farmer review             VISIBILITY
           unsuitable industry? The question            put modular in the spotlight 
           has divided opinion since the                again as part of the solution to                         Peak of inflated expectations
           benefits of modular were hyped up            the building industry’s ills. So is 
           20 years ago.                                modular now climbing Gartner’s 
             In the wake of the 1998 Egan               “slope of enlightenment” to reach 
           report, Rethinking Construction,             the “plateau of productivity”?                                                                         Plateau of productivity
           enthusiasts claimed the quality,               To find out, this study rehearses 
           speed and cost savings achievable            the potential benefits of modular 
           with factory production of                   construction and explores the 
           modular units offered irresistible           barriers that have limited uptake of                                                            Slope of enlightenment
           benefits to the building industry.           prefabrication in the UK – including 
           The anticipated revolution did               a failure to understand the business 
           not happen, and those who                    model and an overwhelmingly                                        Trough of disillusionment
           experimented found the benefits              negative public image. It examines 
           did not always materialise.                  where successes have been 
             The pattern has all the hallmarks          achieved, where they have not and                     Modular trigger
           of the Gartner hype cycle for                where the greatest potential for 
           emerging technologies, which                 future development is.                                                                                                  TIME
            WHAT IS MODULAR CONSTRUCTION?
            Modular construction describes substantial                   Other volumetric modules are “frame + infill”,           structural infill panels are inserted between the 
            elements of a building that are factory-produced           using posts and beams – typically formed from              posts to form the walls, providing greater flexibility 
            and delivered to site for assembly. It comes in            hot-rolled steel sections – to frame the units. Non-       in room layout than a solid-wall module. Floors and 
            several forms – the principal focus of this article                                                                   ceilings span to the perimeter of the frame.
            is volumetric modular systems.                                                                                        n Panel systems (or flat panel systems) – 2D 
            n Volumetric modular systems – prefabrication                                                                         panels are prefabricated, delivered to site and 
            is used to create complete 3D structural units,                                                                       craned into position, then connected to form 
            usually using steel framing or light-gauge steel                                                                      a structure. Materials are typically precast 
            sections but also precast concrete, timber or a                                                                       concrete, timber, cross-laminated timber or 
            combination of these.                                                                                                 structural insulated panels. Finishes and services 
              The modules may be fully fitted out in the factory,                                                                 are usually installed on site after assembly.
            including services and internal fixtures and fittings.                                                                n Pods are relatively small prefabricated 
            They are then driven to the site and craned into                                                                      modules, usually fully fitted out, which may be 
            position, with combinations of modules – often                                                                        used in conjunction with another construction 
            stacked – used to create larger buildings.                                                                            method. Common examples are bathroom or                    VISION MODULAR
              Some volumetric modules have load-bearing                                                                           kitchen pods.                                              TION / 
            walls. They rely on the wall panels for structural                                                                    n Hybrid systems may combine volumetric or 
            strength, either for vertical load bearing or for                                                                     panelised systems with other precast elements 
            diaphragm action to resist lateral loading.                 Mapleton Crescent, by Vision Modular                      and/or a primary structural frame. 
                                                                                                                                                                                             TIDE CONSTRUC
           27.07.2018  BUILDING MAGAZINE 
                                                                                                                                                economics / construction methods / 47
                  02 / POTENTIAL BENEFITS 
                 Speed                                          explained in the next section, below.          Health, safety and wellbeing of staff          can be more easily achieved, resulting 
                 Programme savings of up to 50% are               Savings in labour costs are possible,        In the controlled factory environment,         in improved quality of construction. 
                 possible compared with traditional             by more efficient use of labour or by          risks such as working at height and            There is a reduced risk of moisture 
                 forms of construction. Furthermore, the        avoiding city centre wages. Standardised       exposure to bad weather, noise and             ingress during construction, and 
                 programme can be more predictable              details can reduce overall design fees         dust are reduced or eliminated,                workmanship is not affected by  
                 than when using conventional methods           and a more predictable construction            while other hazards can be better              bad weather. 
                 – if errors do occur during fabrication,       programme reduces the risk of increased        identified and mitigated. Fewer                  Reduced numbers of errors mean 
                 the effect on the overall construction         costs due to delays on site.                   trades and personnel are required in           fewer snags and fewer defects 
                 process can be more easily managed,              The shorter construction programme           the more dangerous site environment.           on handover, and consequently a 
                 since repairs are limited to one particular    can also reduce the costs of site              Also, the workforce in a static factory        reduction in the associated costs  
                 module and can be completed offsite.           management and facilities costs, while         has longer-term job prospects,                 and delays.
                                                                producing a faster return on investment,       extending beyond completion of  
                 Space                                          with reduced financing costs.                  the current project.                           Sustainability
                 A smaller site area is required on site          The manufacturer’s cost base                                                                More construction offsite means less 
                 as fewer construction materials are            should be more predictable as there is         Quality                                        waste as the controlled conditions 
                 stored there. With careful management          greater control of the workforce, who          Assembly in a factory can consistently         enable work to be more precise and 
                 of the delivery and installation of            are likely to be on more permanent or          deliver airtight, thermally efficient          there are fewer mistakes, and waste 
                 modules, temporary storage can be              fixed contracts, than with site-based          construction, with lower running               produced in a factory can be more 
                 minimised or removed altogether.               alternatives where operatives move             costs. The air gaps between modules            easily recycled. On a residential 
                                                                from site to site looking for better pay       in volumetric construction assist in           building, most of the lifetime energy 
                 Cost savings                                   and conditions. Transferring from trade-       providing acoustic separation between          use is due to space heating: the better 
                 The repetitive nature of modular               based delivery to a more task-trained          units. Factory production can deliver          airtightness and thermal performance 
                 construction, which is tailored to a           operative scenario not only reduces            more durable construction, which               obtainable in factory conditions, 
                 factory environment, creates lower             cost but also improves access to labour        requires less maintenance.                     particularly with volumetric modules, 
                 costs – though these savings are               and can help alleviate some impending            In a controlled factory environment,         translates into lower energy use and 
                 not always achieved in practice, as            construction skills capacity issues.           strict quality assurance procedures            lower running costs for occupants. 
                  03 / OBSTACLES TO ADOPTION
                  Cost                                                          to the client. So although costs may come down,               competitive and behave as expected; passing 
                  Feedback suggests that in some areas such as                  prices often remain high – though this “risk                  savings on to “good” clients that adopt the new 
                  Ministry of Defence work, student housing                     margin” is difficult to identify because modular              practices needed to maximise the benefits of 
                  and even budget hotels, modest savings are being              contractors do not provide detailed cost data in              offsite (see figure 2, overleaf).
                  achieved, but in the mass market and                          the same way as traditional contractors. 
                  the emerging build-to-rent (BTR) sector                         On top of this, many clients fail to understand             Negative public perception
                  capital costs remain higher than for                          that modular construction requires a different                The public’s distrust of modular lies in the history 
                  traditional contractor delivery.                              approach to procurement, in which details are                 of prefabrication. Back in the mid-19th century 
                   The explanation lies in the nature of the                    designed with factory construction in mind and                there were spectacular successes: Joseph Paxton’s 
                  business model and – in particular – the current              design is finalised before procurement. This leads            Crystal Palace in Hyde Park for the 1851 Great 
                  lack of competition in the modular market.                    to avoidable extra costs due to late changes and              Exhibition and Isambard Kingdom Brunel’s 
                   The suppliers of volumetric modules are                      costly detailing.                                             wooden Renkioi Hospital built during the                   »
                  operating a manufacturing business with                         As a result of these factors, some clients  
                  large initial investment and relatively high                  see no cost savings, or even pay more, though they 
                  overheads associated with running the factory                 may still receive the programme and  
                  and its fixed labour force. They need, above all,             quality benefits. Indeed, many early users see 
                  a steady flow of work. Keeping unit costs low                 speed of construction (and hence an early 
                  depends on high utilisation, which can be much                return on investment) as the key driver, so  
                  more difficult to achieve in construction than in,            driving down construction cost is seen to be  
                  say, a car factory because the offsite manufacturer           of lesser importance.
                  is multiple steps removed from  
                  the commercial/sales decision making.                         Competition
                   Consequently there can be large variations in                There are a limited number of suppliers, partly 
                  unit costs depending on the level of utilisation. If          because of the reasons above, and capable 
                  suppliers with low utilisation discount too much              competition is lacking (see table 1, page 50). 
                  to generate demand, they go bust, so they tend to             Suppliers try to maximise their profits, so 
                  keep their prices up (see figure 2, overleaf).                in a supply-limited market, prices will rise 
                   When the factory’s utilisation rate is high, unit            to match the cheapest alternative, usually 
                  costs come down. But this corresponds with                    conventional construction.
                  periods of high demand, so there is no financial                As both demand and capacity for offsite                      John Dodgson House, a budget summer residence 
                  incentive for the supplier to pass on the savings             grows, the market will hopefully become more                   owned by UCL and built by Premier Modular
                                                                                                                                               PREMIER MODULAR
                                                                                                                                                                       BUILDING MAGAZINE  27.07.2018
                 48 / economics / construction methods 
          » Crimean War. However, both enterprises               for modular, the space planning, detailed              with that supplier are particularly important.
          excluded Britain’s architectural establishment,        design and service integration all need to be            At present, most UK suppliers use simple forms 
          which may help explain why prefabrication              completed earlier than on traditional projects,        of construction, largely because the industry 
          was not repeated for the next half century, and        since the costs of incorporating late design           is still in its infancy and suppliers are avoiding 
          rarely thereafter.                                     changes to the modules can be very high.               over-investing in heavily automated fabrication 
            In the 1940s, post-war prefab housing was built      Clients who realise this too late find that their      systems. This may help limit the supplier’s risk, 
          quickly to meet an urgent need when materials,         costs rise, or that their required changes are         but it also limits the benefits that full automation 
          labour and money were in short supply. Modular         too expensive to implement.                            could bring.
          came to mean temporary accommodation such                Of course, suppliers try to keep their factories 
          as site huts. Consequently, prefabrication and         full and their utilisation rates high, so once a       Accreditation
          modular came to conjure up images of cheap,            programme of construction has been agreed,             Building regulations, planning permission and 
          cramped construction.                                  it can be difficult to alter the rate of delivery.     insurance and mortgages for residential property 
            The stereotyping has been reinforced by the          Acceleration may be impossible due to other            can be a barrier, as they are with any construction 
          way the recent British volumetric modular              orders, and delay may mean “missing the slot”          innovation, because they take time to catch up. 
          construction industry has developed – emerging         and incurring contractual penalties.                   Mortgage lenders generally expect a design  
          from the temporary accommodation market,                                                                      life for the structure of at least 60 years, while 
          sometimes with few efforts to disguise the fact.       Procurement                                            non-structural components are expected to last 
          Some manufacturers may be unaccustomed                 Once engaged with a particular supplier, there         no less than 15 years. Durability of new systems is 
          to appointing architects with experience of            is usually very little scope to source modules         difficult to demonstrate, but suppliers are able to 
          designing high-quality, permanent buildings and,       from an alternative company if the original            address concerns with the Buildoffsite Property 
          conversely, few architects are familiar with the       supplier fails to perform. So careful choice of        Assurance Scheme (BOPAS) certification or 
          design of volumetric modular units.                    supplier and developing a close relationship           alternative assurance schemes.
          Design
          The most obvious constraint is how large and              Figure 2: Explanation of utilisation and effect on cost and risk
          heavy a module can be. To be transported by lorry 
          each module must be within the limits of 2.9m                A) Current volumetric market position of ‘inconsistent utilisation’
          wide, 4.2m-4.5m high and 18.75m long (or a little 
          larger for an “abnormal load”). A lightweight 
          volumetric unit can usually be lifted by a medium- 
          to heavy-duty all-terrain mobile crane, although                                   (F)
          incorporating concrete floors into the modules                                                                                                  1
                                                                                                                                  Optimum utilisation A
          can double the load. There is also a limit to the                                                                       (C)
          height to which units can be stacked, although the                                     (D)                               (B)
          limit depends on the type of module and the form 
          of construction.                                       (£)                                             (D)
            There can also be constraints on layouts. 
          Some forms of modular construction require                                                                              Optimum cost threshold (E)
          load-bearing partitions to stack vertically through 
          the height of the building, with limited scope                                                                          (A)
          to accommodate large openings in these walls. 
          These also limit the flexibility to alter the layout 
          between floors, meaning, for example, that a late                                 Duration
          change in the mix of apartments for a housing 
          block would have a major effect on the design and                                                                     Risk margin + profit (D)
          could also require further changes to the layout             Optimum utilisation (A1)
          of apartments on the floors above and below.                 Utilisation (A)                                          Excess cost driver by low utilisation
          Greater flexibility can be achieved by combining             Actual cost of manufacture (B)                           Optimum ‘cost’ threshold (E)
          factory fabrication with sub-assembly into larger            Actual price to client (C)                               Comfort/confidence  
          units on site.                                                                                                        (period between utilisation) (F)
            Many facade types and finishes used with                                                       
          modular construction reflect the industry’s            Notes:  
          background in temporary accommodation, with            Actual cost (B) driven by utilisation levels (A). 
          a perception of mere functionality, and lack of        Actual price level (C) driven by confidence – the shorter the period (F) drives a lower risk margin (D) and 
          durability. However high-quality finishes can be       ultimately a lower price. 
          achieved, and a panellised facade system can be 
          fixed to the units after they are installed on site.   In periods where manufacturers risk margin (D) and optimum cost threshold (E) drops below the actual cost of 
                                                                 manufacture (B), losses will be made which if (F) remains wide then a company risks going under.  
          Flexibility                                            The answer/solution is to be able to control utilisation levels through a consistent pipeline:  
          With traditional construction it is common for         n Decrease (F) 
          design to overlap with construction, such as the       n Reduce (B) towards level of (E) 
          design of kitchens and bathrooms continuing            n Ability to reduce (D) 
          while the structural frame is erected. However,        n Reduction in (C)
          27.07.2018  BUILDING MAGAZINE 
                                                                                                                             economics / construction methods / 49
               04 / KEY DRIVERS ON RESIDENTIAL PROJECTS 
               Figure 3: Relative importance of key drivers
                                                                                                                            Graphs A-E illustrate the key drivers on a range of 
                A               Housebuilder                          B          Build-to-rent developer                    residential products, shown on a scale of one to 10 
                                     Time                                                  Time                             against the headings of cost, quality, and time. 
                                 10                                                    10
                                  8                                                     8                                   For example, a housebuilder places high emphasis 
                                  6                                                     6                                   on cost base, but less on programme due to a 
                                  4                                                     4                                   consistent pipeline and a requirement to phase  
                                  2                                                     2                                   units to market, whereas a build-to-rent developer 
                                  0                                                     0                                   places much greater importance on bringing units  
                                                                                                                            to market quickly.
                Quality                             Cost              Quality                            Cost
               C             Student housing                          D           Mass market developer                     E              Prime residential developer
                                     Time                                              10Time                                                 10Time
                                 10
                                   8                                                     8                                                      8
                                   6                                                     6                                                      6
                                   4                                                     4                                                      4
                                   2                                                     2                                                      2
                                   0                                                     0                                                      0
                 Quality                            Cost              Quality                              Cost              Quality                             Cost
               05 / WHAT IS MODULAR CONSTRUCTION SUITABLE FOR? 
                                                                                                 Success stories                           Accommodation Modernisation), 
                                                                                                 Take-up has been generally at the         an accommodation programme for 
                                                                                                 lower end of the market, wherever         the Ministry of Defence taking in 
                                                                                                 repetition is achievable, speed           52 locations across the UK.
                                                                                                 of construction is particularly 
                                                                                                 desirable and high quality is not         Areas for improvement
                                                                                                 necessary. Examples include               It has had little or no take-up in 
                                                                                                 student accommodation, where              commercial offices, where large, 
                                                                                                 Vision Modular has delivered a            open interior spaces are required 
                                                                                                 number of successful schemes              and where, most significantly, the 
                                                                                                 such as Apex House and Felda              market is highly cyclical, providing 
                                                                                                 House in Wembley, north-west              little or no potential base-load of 
                                                                                                 London, as well as Chapter in             utilisation for a factory. 
                                                                                                 Lewisham, south-east London.               Nor, so far, has modular had much 
                                                                                                   In key worker accommodation             impact in markets where speed 
                                                                                                 both Premier Modular and                  of construction is less critically 
                                                                                                 Caledonian have delivered                 important, including the middle to 
               VISION MODULAR                                                                    schemes at Hinkley Point for              upper range of the housing market 
               TION /                                                                            construction workers at the               (apart from details such as toilet 
                                                                                                 nuclear power station. Pocket             pods and prefabricated facades). 
                                                                                                 Living’s Mapleton Crescent                 Benefits have been 
                Apex House, Wembley, student accommodation,                                      scheme in Wandsworth, south-              demonstrated in terms of  
               TIDE CONSTRUCwhich is the tallest modular building in Europe                      west London, was completed by             snag-free compliance and 
                                                                                                 Vision Modular.                           functionality, but few are 
               Modular’s level of suitability            three areas – time, quality and cost      Budget hotels such as Premier           convinced that modular can 
               for different projects can be             – but in practice there is always a     Inn and Jurys Inn have been               provide the less tangible aspects 
               explained by the traditional              trade-off. Modular offers potential     constructed using volumetric.             of high-quality development – to 
               construction triangle of quality,         benefits in all three areas, as         Other notable schemes include             create spaces that people really 
               cost and programme (figure 3,             explained in the “Potential             a number of schools and                   want to live and work in and that 
               above). The ideal is to optimise all      benefits” section (page 47).            Project SLAM (Single Living               people delight in.                    »
                                                                                                                                                  BUILDING MAGAZINE  27.07.2018
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...Economics analysis facts forecast construction methods modular is touted as the future of building industry but while sector rapidly growing in some areas there are still obstacles to overcome alex hyams alinea ed mccann expedition engineering and hugh ferguson assess pros cons volumetric offsite introduction shows way technology figure gartner hype cycle showing a s journey for uk its adopted with peak inflated mainstream acceptance supporters have long maintained expectations followed by or it hopeless effort translate trough disillusionment see factory techniques into an farmer review visibility unsuitable question put spotlight has divided opinion since again part solution benefits were hyped up ills so years ago now climbing wake egan slope enlightenment reach report rethinking plateau productivity enthusiasts claimed quality find out this study rehearses speed cost savings achievable potential production explores units offered irresistible barriers that limited uptake prefabricat...

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