Off-site manufacture for construction: Building for change Contents

Chapter 3: Infrastructure, building and housing


Hospitals, schools and prisons

46.Off-site manufacture is suitable in many cases for construction of important social infrastructure such as hospitals, schools and prisons. If the benefits set out in Chapter 2 are realised, off-site manufacture could be used to build better quality, more user-friendly facilities leading to better outcomes for clients and users. In Boxes 1 and 2 we set out several case studies that we received in evidence.

Box 1: Dumfries and Galloway Royal Infirmary

The Dumfries and Galloway Royal Infirmary (DGRI) was constructed using off-site manufacture. This led to the following benefits:

Time—A 30-month construction programme for DGRI was six months shorter than traditional construction, resulting in reduced overheads and labour costs.

Value—an earlier completion date provided significant savings to DGRI’s operating costs and rental cost on existing buildings.

Standardisation—use of repetitive components reduced the number of component types and interface details, making more effective use of resource and increasing output.

Improved health and safety—significantly reduced vehicle movement and crossover of trades on-site. Installation of external wall panels, structural frame and suspended floor planks manufactured off-site meant that no scaffold was required on DGRI, reducing the risk of falls from height.

There were, however, some drawbacks:

Remedial work was required to bathroom pods to replace wall linings damaged during construction or affected by water ingress. Temporary weather protection needed to be addressed and considered more thoroughly to reduce impact.

The intention on DGRI was for panels to be craned immediately from delivery to installed position; however this often was not practical, so additional storage on-site was required.

Source: Written evidence from Ryder Architecture (OMC0067)

Box 2: Other examples

Royal Victoria Building, Western General Hospital, Edinburgh

A 20-week reduction in programme length, where 55% of the project was manufactured off-site and was delivered with a team that was 25% smaller with zero accidents.

Reigate Primary School

The main building structure took five weeks to complete and the school was completed 14 weeks early by achieving the best combination between off-site and on-site assembly.

Witham Railway Station

A new booking hall structure was created within one week on-site, compared to the eight weeks required for traditional techniques. The station superstructure was completed within a three-week programme on-site to reduce impact on station users.

West Hill School, Surrey

A challenging sloping and highly restricted site at West Hill School was developed to link the original special needs school and an existing modular building with a new classroom block. The building was manufactured off-site and was ready for occupation on time and after less than eight months on-site. Both buildings either side of the new facility remained fully operational throughout. The project made extensive use of BIM and virtual reality, which facilitated early decision-making with stakeholders and helped to engineer an off-site solution which addressed the complexities of the site.

Source: Written evidence from Mott MacDonald (OMC0069), Osborne Group Holdings Ltd (OMC0023) and McAvoy Group (OMC0047)

Horizontal infrastructure

47.As well as being used for buildings, off-site manufacture provides significant benefits for horizontal infrastructure such as roads, railways and utilities. In Boxes 3 and 4 we set out case studies that show how the benefits of off-site manufacture were realised.

Box 3: Crossrail

Platforms at Tottenham Court Road and Liverpool Street stations were delivered for the Crossrail programme. Both stations had similar scope, but the 250-metre platforms were built using very different methods, the former relying on traditional in-situ construction; and the latter applying Design for Manufacture and Assembly solutions, where 460 precast concrete elements were manufactured in a controlled factory environment.

The off-site approach delivered an 11-week programme saving, with fewer people required to work underground and reduced occupational health risk. The Tottenham Court Road platform took 67,000 man hours to complete whereas the Liverpool Street platform took 27,000 man hours.

Fifty-seven skilled operatives were required to deliver the in-situ installation at Tottenham Court Road. At Liverpool Street there were seven people on-site (the skills of those seven people were not traditional concrete-laying skills. These were people who understood logistics, assembly and manufacturing-type techniques. They walked along large craneages that lifted big components in place and put them in place against the digital model) and 27 people in the factory.

Source: Written evidence from Laing O’Rourke (OMC0055) and Q 59 (Andrew Wolstenholme)

Box 4: Other examples

Davyhulme wastewater treatment works

A 10–20% reduction in raw materials was achieved by using off-site manufactured elements (for example, thinner, higher performing wall panels), while saving three months on project delivery.

Ordsall Chord

By adopting a fully digital approach to delivering the Ordsall Chord viaduct in Manchester, the project programme was reduced by 20% and costs by 15%, while eliminating site queries and associated costs and delays.

Source: Written evidence from Mott MacDonald (OMC0069)


48.Housing has become an increasingly pressing issue in recent years. In the Autumn Budget 2017 the Chancellor announced a target of delivering 300,000 additional homes a year by the mid-2020s, with a series of financial incentives to help achieve this.

49.Witnesses told us that off-site manufacture would be the only way to meet this target, and that traditional construction does not have the capacity to build enough homes.55 However, we were also told that off-site manufacture is currently most suited to mid- to high-rise buildings rather than individual small homes.56 This is in part because there is more certainty in the pipeline of projects for these types of homes, often driven by housing associations57 and build-to-rent, compared to individual homes.

50.Dr Chris Goodier and Professor Alistair Gibb from Loughborough University highlighted how off-site manufacture could reduce the flexibility of housebuilders to respond to changes in the housing market, both locally and nationally:

“The longer lead-times associated with offsite methods (i.e. the early design freeze and the offsite manufacturing stage) requires the housebuilder (usually) to commit to a production schedule significantly in advance of actual unit sales. When market conditions deteriorate (which they always will at some point, and which housebuilding firms are acutely aware of and sensitive to), or do not grow as anticipated, off-site housebuilders may find it difficult to reduce unit output and thus expenditure. The risk of committing to production early is a concern for housebuilders looking to adopt off-site—there is a risk that they will no longer have full control of production, and hence financial outlay, on site.”58

51.We were also told about the concerns of mortgage lenders regarding lending for homes built using off-site manufacture. The Building Societies Association told us that the concern of lenders is “the accurate valuation of properties using MMC [modern methods of construction] and the existing provision of building warranties to ensure lenders and borrowers have cover in the wake of something going wrong with a building”.59 UK Finance told us:

“some types of non-traditional construction have a relatively poor track record compared to more traditional construction methods. This can lead to lenders, whether they are providing individual mortgages for home-ownership, or finance for newly built property in the social rented sector, to take a cautious approach to new methods of construction which do not have a proven track record.”60

As a result, there have been calls for some form of industry accreditation or sign-off body for off-site manufactured housing.

52.We recommend that the Government explore options for the accreditation of housing built using off-site manufacture, to ensure that mortgages are available to those who wish to purchase them.

53.To increase the use of off-site manufacture in the housing sector the Government could put pressure on housing associations, through conditional funding, to use off-site manufacture. Richard Harrington MP, Minister for Infrastructure and Construction at the Department for Business, Energy and Industrial Strategy (BEIS), told us that “while housing associations are independent in their legal standing, it is quite right that government should apply conditionality to the money that they spend. That is why I am seeing Homes England about it”.61 It was also suggested by Jane Richards, Director of Building Structures at WSP UK, that the Government could mandate that a certain proportion of housing be built using off-site manufacturing in large regeneration projects.62

54.In the Construction Sector Deal the Government sets out that it will provide £15 billion of new financial support for housing over the next five years, taking total financial support to at least £44 billion to 2022/23. Furthermore, it will “ensure that … funding for the Transforming Construction programme supports the development and commercialisation of technologies and digital building designs that can help deliver the government’s housing objectives”.63 However, the Sector Deal gives no detail about how the additional funding for housing will be used to drive the uptake of off-site manufacture and other technologies, which are part of the three strategic areas of the Sector Deal (see paragraph 5).

55.The Government must set out what conditions it will attach to the extra financial support for housing to drive the uptake of off-site manufacture and other innovative technologies.

56.We recommend that the Government, through Homes England, put pressure on housing associations and local authorities to stipulate the use of off-site manufacture, where appropriate, when procuring new housing developments. It should also consider mandating a proportion of off-site manufacture for large regeneration projects.

57.In Boxes 5 and 6 we set out several housing case studies that we received in evidence.

Box 5: Kidwells housing estate

One housing group needed to replace 84 homes and add a further 120 apartments. The new homes for existing tenants had to be built without the tenants moving off-site during construction.

Minimising onsite disruption was important and several noise restrictions were imposed. An energy-efficient, convenient and cost-effective, off-site manufactured infill system was adopted for the concrete framed structures.

Source: Written evidence from Osborne Group Holdings Limited (OMC0023)

Box 6: Athletes Village for the 2014 Commonwealth Games

As part of the City Legacy Partnership, 237 units were delivered across the Athletes Village for the 2014 Commonwealth Games in Glasgow. These 237 units were fully completed in 292 days. Coupled with the speed of construction each unit was designed to allow flexibility of use. During the international sporting event the units were required to be utilised in ‘Games Mode’ sleeping up to 12 athletes and post-games the units were transformed to ‘Legacy Mode’ providing a mix of two, three and four-bedroom houses.

The design brief and environmental strategy set by the client was to achieve zero carbon and a 60% reduction on the standards required by the 2012 building regulations. Carbon dioxide emissions were reduced by approximately 30% reduction compared to a typical house. A further 30% reduction was driven by the use of renewable technologies such as Mechanical Ventilation with Heat Recovery and photovoltaics roof panels. This project was delivered ahead of programme within the budget set by the client.

Source: Written evidence from CCG OSM Ltd (OMC0009)

International Comparisons

58.Ann Bentley, Global Practice Director at Rider Levett Bucknall, told us that the commercial construction sector in the UK is “as advanced as anybody” globally on off-site manufacture. She went on to say the in the high-rise residential sector the UK is “quite advanced” but that in the low-rise residential sector the UK is “substantially behind Scandinavia, North America and Japan”.64

59.David Hurcomb, Chief Executive of NG Bailey, explained that a disruptor in the construction sector, using off-site manufacture, is “most likely to come from overseas, and perhaps from China”.65

60.There is an opportunity for the UK to maintain its position at the forefront of off-site manufacture globally in the commercial and high-rise residential sectors. However, we are concerned that the UK lags significantly behind other countries in the low-rise residential sector. The Construction Leadership Council and the Government have an important role to play in encouraging the use of off-site manufacture in the low-rise residential sector. This can be done by the spreading of best practice and case studies by the CLC and by the Government providing incentives to house-builders.

56 Q 10 (Jamie Ratcliff)

57 Written evidence from Swan Housing Association (OMC0076) and Accord Housing Association (OMC0079)

58 Written evidence from Loughborough University (OMC0032)

59 Written evidence from the BSA (OMC0049)

60 Written evidence from UK Finance (OMC0051)

61 Q 77 (Richard Harrington MP)

62 Q 33 (Jane Richards)

63 Department for Business, Energy and Industrial Strategy, Construction Sector Deal (5 July 2018): [accessed 5 July 2018]

64 70 (Ann Bentley)

65 Q 44 (David Hurcomb)

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