THE LAST WORD
– in those circumstances production may need to be swift.
Helpfully, today’s Modern Methods of Construction (MMC) systems have been developed to meet specific needs – such as improved environmental performance – but a frequent by-product is that they also enable speedy construction. MMC is not flawless though and cases of systemic failure due to the implementation of MMC has generated criticism of these measures.
Therefore clients, design teams and contractors must balance the potential risks – from fire safety to Building Regulations compliance – of such systems with their benefits – such as increased thermal or acoustice performance, or reduced community impact. Doing so effectively will help teams ensure they present durable, low-maintenance solutions which will provide a healthy internal environment for occupants over the lifetime of the building.
THE RISKS AND REWARDS
In Building sustainable homes at speed the NHBC
Foundation analyses a range of case studies using MMC. The report considers some of the key rewards and risks of building homes quickly and sustainably, from the design phase, through procurement and into construction.
The CASPAR II project in Leeds, for example, was an attempt to develop an apartment block for the private rented sector which could be available
for below market rent and still make an attractive return on investment without any subsidy. It was based on volumetric and panelised construction, which was intended to achieve greater efficiencies. While the project received critical acclaim and positive feedback from residents, defects emerged – such as to its stability and flooring – which led to a series of investigations into the construction of the building. Ultimately it was felt that the time pressures under which the scheme was developed, may have contributed to its problems.
A further example is the Castlefields Estate Regeneration Project in Runcord which is a
development that uses timber frame construction. This long- term, multi-phase project was not without issue; one of which was that, due to its scale and size, the project needed to accommodate ongoing adaptation and design changes, yet an adaptable product was not easy to find for a reasonable price in the market. However over the lifetime of the project, many issues were overcome and the various phases of construction showed an increasingly sophisticated approach to closed panel timber frame construction. This was in part due to effective long-term
relationships and collaborative working between contractor, client and design team, which enabled the transfer of lessons learned from one phase of construction to the next. As a result, the last phase was largely defect free.
RECOMMENDATIONS
The NHBC Foundation advises that much can be gained from the sharing of best practice learnt over many years of speed building and MMC, both within and among project teams. It is critical that at all stages of the construction, all parties employed in the project are fully integrated and the appropriate skill needs are met.
In particular, thorough planning is important from the outset, in order to take due account of potential long-term risks and maintenance issues. All component interfaces must be considered carefully at design stage to ensure correct interface solutions are devised and incorporated into the design. Finally, there must be a full review of the whole plan before pressing ‘GO’.
CONCLUSION
Social housing has seen the greatest experiment with rapid construction methods. It is RPs who have developed some of the most successful techniques for dealing with risk and have a vested interest in reducing long-term maintenance has driven a focus on reducing defects.
The advantages of building quickly are obvious: short construction programmes mean existing residents are not displaced for too long and new occupants are usually available to move in straight away. However, RPs are increasingly aware of their potential liabilities including the need to preserve funds for the
maintenance and refurbishment of their existing stock.
Private developers offering new housing to home-owning customers in the UK have, in general, had a more difficult time justifying some of the risks necessary to build quickly. Ultimately, for some clients, judgements about whether breaking with conventional methods was a risk worth taking will have to wait some years. Then we can judge whether a focus on innovation and speed has produced durable and healthy homes that can stand the test of time.
Image: CASPAR II project in Leeds (Volumetric units)
The NHBC Foundation was established in 2006 by NHBC in partnership with the BRE Trust. Its purpose is to deliver high-quality research and practical guidance to help the industry meet its considerable challenges.
Since its inception, the NHBC Foundation’s work has focused primarily on
the sustainability agenda and the challenges of the government’s 2016 zero carbon homes target. Research has included a review of microgeneration and renewable energy techniques and the groundbreaking research on zero carbon and what it means to homeowners and housebuilders. The NHBC Foundation is involved in a programme of positive engagement with government, development agencies, academics and key stakeholders, focusing on current and pressing issues relevant to the industry. With 50 publications to date, the NHBC Foundation also supports the industry by leading debate and thinking among industry experts, reporting on key and pressing issues relevant to the homes of the future.
NHBC Foundation’s Building “Sustainable Homes at Speed: Risks and Rewards” is
available to download at
www.nhbcfoundation.org /buildinghomesatspeedt
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