MAKING MODULAR STACK UP: MODERN METHODS OF CONSTRUCTION IN SOCIAL HOUSING

Transcription

1 MAKING MODULAR STACK UP: MODERN METHODS OF CONSTRUCTION IN SOCIAL HOUSING REPORT Sonja Oliveira, James Burch, Karl Hutchison, Olalekan Adekola, Suha Jaradat and Matthew Jones Centre for Architecture and Built Environment Research, Department of Architecture and the Built Environment, University of the West of England

2 ACKNOWLEDGMENTS The authors wish to thank the support and guidance of the Steering Group members Elena Marco and Prof Bill Gething. This report was prepared for a partnership of seven housing associations from across the East of England. Flagship Group led the project with invaluable contributions from Cross Keys Homes, Freebridge Community Housing, Havebury Housing Partnership, Longhurst Group, Saffron Housing Trust and Victory Housing Trust. The University of the West of England, nor any of its personnel, affiliated partners or subcontractors shall make any warranty or representation, or have any legal liability or responsibility for the completeness, accuracy, or fitness of any information, product or process disclosed. Reference made in this report to any specific commercial product, service or process by trademark, manufacturer or otherwise does not necessarily constitute or imply its endorsement or recommendation. The views and opinions of authors expressed herein do not necessarily state or reflect those of the partnership nor its constituent members. 2 Making modular stack up: modern methods of construction in social housing

3 FOREWORD The shortage of good quality, affordable housing in the UK is well documented. Around 1 in 10 people in England live in a housing association home and those organisations have a vital role in helping to increase the supply of housing. In February 2017 the UK government highlighted innovative construction techniques as an important step towards building more homes. Supported by a partnership of housing associations in the East of England, Flagship Group commissioned the University of the West of England to investigate the potential future of modern methods of construction (MMC) in social housing. The main objectives of the research were: To review existing literature on MMC and summarise the wealth of current knowledge. To investigate new data on different technologies and construction processes through case studies from the UK. To draw conclusions on the potential of MMC in the social housing sector and make recommendations on how to proceed. This report is the culmination of that research and is the first of its kind in the social housing sector. It demonstrates our desire to innovate, to play our part in building homes that people love and to do so faster and to a higher standard than ever before. For more information contact: Jack Weaver Public Affairs Advisor at Flagship Group Jack.Weaver@flagship-group.co.uk Making modular stack up: modern methods of construction in social housing 3

4 SUMMARY The purpose of the research is to review the application of Modern Methods of Construction (MMC) in housing, particularly in relation to diverse methods of delivery, lending approaches, customer satisfaction and long-term management/maintenance. A review of existing literature is followed by brand new data from case studies followed by conclusions and recommendations. 4 Making modular stack up: modern methods of construction in social housing

5 WHAT ARE THE DIFFERENT MMC CONSTRUCTION METHODS? Mode of delivery Description Open Panel A structural frame using panels constructed in the factory and delivered to site for assembly. Services, insulation, internal finishes installed in situ. Closed Panel Similar to open panel but with more factory based fabrication. Linings, insulation and even some internal finishes, doors and windows can be pre-installed. Volumetric The most factory based form of production. Three dimensional modules used in isolation or in multiples. These can be pre-finished with all fixtures and fittings. Hybrid A combination of volumetric and panelised systems. High value areas (kitchen, bathroom etc.) are formed from a pod and the rest uses panels as a frame. Sub-assemblies Major elements manufactured off-site but not part of the primary structure. E.g. foundations. Components Non-structural elements assembled off-site. Less common but can include mechanical or electrical services. Each delivery method is dependent on choice of material, context (e.g. urban vs suburban), team capabilities and capacity as well as transport. For example volumetric systems are particularly good for high rise or student accommodation. Making modular stack up: modern methods of construction in social housing 5

6 THE PROS AND CONS OF MMC Build quality is comparable to traditional building. 86% of large housebuilders would opt for MMC if end-quality was the only consideration. The benefits of MMC depend largely on the delivery method chosen. However, when MMC is viewed as a whole the following factors are commonplace: Advantages Disadvantages Simplified construction processes Reduced time on-site Waste reduction up to 30% High levels of consistency Energy performance Reduced risks on-site Improved working conditions Longer lead times High set up costs Negative stigma Limited manufacturers Long distance transport Low tolerances/margins for error Difficult to finance 6 Making modular stack up: modern methods of construction in social housing

7 Advantages of MMC delivery such as potential cost reduction are mainly seen in construction costs, rather than design, research and development etc. There is limited evidence on life cycle costs. Time spent in design and offsite manufacture can increase significantly whereas savings can be made in time on-site (see design/build timeline below). Making modular stack up: modern methods of construction in social housing 7

8 WHAT THE BANKS THINK Lender s views are influenced by the verdict of valuers, insurers and warranty providers they are still undecided on the viability of MMC. Mortgage providers are nervous about sharing financial responsibility with homeowners. They would prefer that the house builder retains a long term stake through a joint venture or other partnership. WHAT CUSTOMERS THINK There has been no major study of customer satisfaction with MMC in the UK since 2003 when 46% of social housing tenants objected to being offered an MMC home. More recent small studies have only focused on customers view of MMC, not their experience. LONG TERM MAINTENANCE There is no significant difference in maintenance requirements between traditional building techniques and MMC. Maintenance difficulties can emerge in the interface between offsite manufacture and onsite assembly. The transport of components to site and incorrect assembly can cause issues later. This is largely due to human error rather than shortcomings in MMC. Use of Building Information Modelling (BIM) is key to successful installation and maintenance of MMC. (BIM allows architects, manufacturers, contractors and asset managers to share information about a building through a digital representation of it. Something of a cross between technical drawings and Computer Aided Design (CAD). Sustainable design requirements will soon become increasingly important regarding climate change. 8 Making modular stack up: modern methods of construction in social housing

9 CONCLUSIONS FROM CASE STUDIES Making modular stack up: modern methods of construction in social housing 9

10 METHODS OF DELIVERY Choices on particular methods of delivery are driven by established relationships with particular manufacturers and clients who favour a particular material. This material will in turn lend itself to a particular method of delivery. In one respect this can narrow focus, negatively limiting choice for the client. On the other hand it can build significant experience with a particular material (e.g. steel frame modules leading to a volumetric method of delivery). BUSINESS MODELS & PROCUREMENT Here the case studies echo some of the observations made in the literature. In particular with difficulties in procuring MMC due to established ways of working amongst mainly private housebuilders. Participants in the case studies observed the need for new procurement routes and an acknowledgement of the important place a manufacturer has in the process (in comparison to a contractor in traditional builds). CUSTOMER NEEDS Customer needs were largely viewed as implicit and part of the design process. In most instances, needs were viewed as dependent on the client and/or brief set. Private housing developers were seen not to participate in most cases in discussions on customer needs; whereas housing associations were viewed as active contributors often with predefined criteria. In some cases, criteria were described as problems to avoid rather than ambitions to aim for. LONG TERM MANAGEMENT Long term management was similarly viewed as either dependent on client preference of method of delivery and or choice of material. Obstacles were seen in how products were warrantied. For example one module may include an array of products (taps, lighting, furniture etc.) all with different warranties. This can create difficulty in the event of damage/defects. 10 Making modular stack up: modern methods of construction in social housing

11 RECOMMENDATIONS It is recommended that a clear business case is developed including: It is recommended that a pilot project is procured in order to test and develop capabilities. Start working on innovative business models now. Successful MMC for housing associations will require joint ventures and partnership working. Aftercare is important. Take time to speak to the staff assembling homes and the customers living in them. Overall a number of areas are identified as needing further research: Post occupancy evaluations (POEs) of customers who have lived in modular homes. Find out what they liked and disliked. Understanding of the differences in design and build processes mapped against different methods of delivery. Making modular stack up: modern methods of construction in social housing 11

12