This week’s BDOnline reported how architects have poured scorn on the government’s plan to create incentives for the use of off-site construction. AWW Residential Sector Director, Phil Bevan, comments and talks about how AWW has successfully used off-site construction on our buildings.
The biggest stumbling blocks that are holding back the delivery of new inner-city housing are; the availability of sites at realistic prices, lack of funding to enable developers to build, and the large deposits required by first time buyers. Off-site construction has a valuable role to play in the future of building residential and other projects, but not before more fundamental issues are resolved.
AWW has used modular construction on a number of our buildings, including residential projects, with great success. AWW was involved at a very early stage of the design process of the Surrey Street Bridge House and The Exchange developments in Surrey Street, Croydon. The design of the site included the conversion of a telephone exchange into 42 luxury apartments and the provision of a second block of apartments adjacent to a multi storey Car Park consisting of 25 Affordable and 20 higher value apartments for commercial sale. AWW assessed the optimum site use in consultation with the planners and Bridge House, is an entirely volumetric modular design. Our Surrey Street projects were shortlisted for RICS South East Award 2011 in the Regeneration and Community Benefit categories.
Offsite construction has many advantages and has been promoted for many years as a means of reducing waste and improving construction programmes. The large scale building programmes of the 1960s utilised a form of systematised prefabricated construction like CLASP or SCHOLA to reduce timescales and introduce economies of scale to address the problems faced by a national school estate that had not seen significant investment since before the war.
On all AWW hotel projects, a range of modular solutions are investigated as modular construction enhances the sustainability credentials for any hotel project bringing together an environmentally responsible product of high quality with a reduced carbon footprint. At The Cornwall Hotel, a flat pack timber cassette was used both for the woodland Lodges, and for the 56 bedroom extension behind the original Manor House to minimise disruption to the surrounding Victorian woodland and wildlife. We have used full volumetric modular only for bathroom pods at Morn Hill Holiday Inn and at all three Future Inns Hotels; Plymouth, Cardiff and Bristol.
A recent example of our promotion of an off-site solution was for a major healthcare scheme. The layout had developed from a very efficient floor plate with a rational grid layout around a central atrium. We identified that there may be efficiencies offered by pursuing an off-site solution and undertook site visits and analysis of the various systems available. A German model was eventually selected, which offered extremely high quality, and the slight increase in capital cost was more than offset by the 50% reduction in the construction programme, enabling the client revenue stream to kick in earlier, with consequently a significant improvement in the overall project viability.
Offsite construction, whether modular or prefabricated, requires a highly detailed design at an early stage; the ability to influence the design as it progresses is reduced and the flexibility that may be required in the design or space planning could be compromised. Planning or ecological considerations can often diminish the advantages offered by prefabricated systems as they may need adaptation or extension to allow for a particular roof profile required by a planning condition or the need to include bat roosts. A highly competitive construction bidding environment as pertains currently, can also work against the cost advantages of modular construction when sub-contractors may be able to obtain materials and skills at significantly cheaper rates locally and may not be affected by an adverse sterling exchange rate.
In our experience, the benefits of offsite construction are the speed of delivery, and the quality and safety of the workforce. However this does come at a price, and recent experience has shown that where the programme permits, it is still cheaper to build traditionally.