Mon 1 Oct 2007
Modernising methods of construction
Now the pressure is on to build more houses more quickly and more sustainably, timber, steel and brick and block manufacturers have been busy adapting their products. Roger Hunt reports."High demand for quality housing requires fast and effective building and is forcing the construction industry to rethink the processes by which modern housing is delivered," asserts Adam Newton, managing director of Framing Solutions.
"While off-site technology is gaining considerable ground, as an industry we only stand to gain further by moving away from the temptation of pitting the benefits of one material against another. Instead we should be rather more concerned with profiling collectively the ways in which off-site methods offer a viable alternative to traditional methods of construction."
"Experience at Framing Solutions shows that some of our most successful schemes to date have benefited from an approach where we have worked with clients from an early stage in the design process to identify the combined benefits of steel, concrete and timber in one hybrid structure."
Framing Solutions, a joint venture between Corus and Redrow, has been awarded upgraded certification from the British Board of Agreement to confirm its Surebuild lightweight steel framing system can be used in structures of up to six storeys. The system is enveloped in thermal insulation panels with factory-built cassette floors and has an option for a habitable roof.
Fusion Building Systems has recently launched Fusion Therma Shield 162, a new, pre-insulated, 162-millimetre panel, light gauge steel building system. Achieving a U-value of 0.21W/m2K, the product is precision engineered to meet and exceed building regulations and is claimed to deliver robust, energy-efficient, airtight buildings.
"If we are to successfully meet the targets set out in the Housing Green Paper for increasing the UK's housing supply by three million over the next 13 years, then modern methods of construction [MMC] will have to be considered on a wider scale than at present," believes Robert Clark, Fusion Building Systems UK's general manager. "With a relatively low current market share, we strongly expect the number of steel-framed homes being constructed each year to increase as the industry works towards achieving this target."
Mark Shea, managing director of Light Steel Frame Solutions (LSFS), a national provider of light steel-frame structures, thinks the lack of skilled tradesmen in the UK is resulting in a real need to deploy fewer workers on-site.
"Quicker build times and reduced on-site labour offered by innovative off-site construction techniques has therefore made light steel-framing technology a popular option among many UK specifiers and contractors."
The LSFS (STRUCMET) system uses prefabricated components resulting in economy of scale in production. Realising the need to deliver even shorter build times, LSFS has forged a strategic partnership with Elements Europe, a manufacturer of factory-assembled, modular kitchen and bathroom pods. The pods benefit from lightweight structural steel wall panels while incorporating fully finished kitchens, bathrooms, en suites and airing cupboards as integrated structural component of the building.
From Corus comes Corefast, a rapid-erect modular steel/concrete composite system using the company's Bi-Steel panels to facilitate the rapid construction of structural cores from three to over 100 storeys and any combination of lift cores and stairwells. The Corefast core is created by fabricating Bi-steel panel modules off-site. The cores can then typically be erected up to six times faster than an equivalent concrete core as the Bi-Steel components are assembled and concrete filled without the need for formwork. Hanson has developed QuickBuild, a brick and block cavity wall that is prefabricated off-site and craned into place. The system can provide panels up to nine metres long, both plain and with openings, and was used in the construction of the Hanson EcoHouse at Offsite 2007 at the Building Research Establishment. The prefabricated cavity walls comprise 100-millimetre stack-bonded Hanson clay facing brickwork outer leaf, 100-millimetre Thermalite aircrete blockwork inner leaf and a partial fill cavity with 100-millimetre rigid insulation and a 50-millimetre air space.
With the emphasis on sustainability, Baggeridge is offering two bricks that are manufactured using 100 per cent recycled material. Its Kingsbury Smooth Cream and Kingsbury Classic Cream both utilise fireclay, a waste product generated from mining.
Mark Morris, sales director for Baggeridge, firmly believes that the benefits of clay in manufacture far outweigh those of rival materials. "The use of clay in building is a way of ensuring natural resources are used to their full potential while also helping to reduce energy costs. Clay has high thermal mass properties compared to some other types of masonry."
Due to fast-growing demand, Lime Technology has announced that its Sumatec range of compressed earth blocks will now be exclusively manufactured by Ibstock. Produced from a mixture of earth and clay that has been deemed unsuitable for brickmaking, they have very low embodied energy. Designed to be laid flat, the blocks have a compressive strength of 17 newtons per square millimetre. If tied into another leaf of masonry or timber frame they can also be laid on their edge, offering a compressive strength of three newtons per square millimetre.
From the housebuilder's perspective Linden Homes South East has, over the past three to four years, implemented a major change in the way it builds its homes; moving from traditional brick and block construction methods to timber frame on more than 95 per cent of its homes this year.
For Paul Cooper, managing director of Linden Homes South East, the primary objectives for using conventional open-panel timber frame are to quicken build times and increase the energy efficiency of its homes. "It has enabled us to achieve both these goals, while keeping the end result looking much the same as masonry construction from the outside.
"Our current flagship scheme, Water Colour in Redhill, represents an entire community built on timber-frame construction. The limited on-site waste achieved with timber-frame was a major positive for the new 500-home brownfield development in the Surrey countryside but, as there is less work to do on site, timber-frame also lends itself well to smaller inner-city developments where there is limited space for materials and waste."
Garry Dyke, national product manager at Palgrave Brown, a supplier of timber-engineered products, sees the SIPs (structural insulated panel) system as a next generation product and indicative of the direction the construction industry will take. "It incorporates all the benefits of modern methods of construction, as the panels are manufactured off-site and go together extremely accurately for fast build times. "For housebuilders, one of the main benefits of the SIPs system is that the low U-values combined with excellent airtightness make it easy to improve on carbon emissions ratings needed to meet the requirements of Part L."
The Palgrave Brown SIPs building system incorporates the Kingspan TEK SIPs system and is complemented by a full range of engineered timber products for a complete floor-to-roof solution.
Eleco Building Components is manufacturing ElecoFrame a timber-frame system utilising high-grade structural timber using connector plates provided by sister company Gang-Nail Systems. Panels are supplied to site as open frames, removing the need for sheathing board on the external face of wall panels. Diagonal bracing and engineered nail plates mean that the overall structure is more rigid than conventional timber-frame systems.
Adrian Booty, commercial director at Cotswoldgate, is another housebuilder to cite a preference for timber. "We currently use timber-frame across 50 per cent of our sites. The remainder of our smaller sites use traditional build in a combination of stone, brick and render.
"The environmental benefits of timber-framed houses are gaining increasing prominence when choosing a home. The long-term environmental benefits of energy-efficient design and technology is something all developers have to consider increasingly, given the introduction of the Code for Sustainable Homes, which is driving a step change in sustainability within the construction of new homes," says Booty.
Space4, which claims to be the UK's largest producer of prefabricated housing and specialises in serving the technical needs of the mass-market housebuilding industry, is offering a portfolio of products that mean customers can pick and choose the house type that best suits their needs and build almost any mass house design that would traditionally have been constructed in blockwork masonry. Patrick Dormon, Space4's managing director, sees the use of timber-frame as offering an excellent start in reducing the carbon footprint of a home. "It helps to tackle the energy and carbon dioxide emissions, reduces sound pollution and, through the provision of environmentally friendly materials, means the targets for the Code for Sustainable Homes are being addressed.
"It is due to this that I believe timber-frame homes will continue to go from strength to strength. However, it is only through a true industry partnership that we will ever meet the government's six-star rating."
First published in Show House Magazine October 2007.
The greatest care has been taken to ensure accuracy but some information contained within this article may have changed since it was first published.
Posted by Roger Hunt
in Baggeridge, Corus, Eleco Building Components, Elements Europe, Features, Framing Solutions, Fusion Building Systems, Hanson, Light Steel Frame Solutions, Lime Technology, Palgrave Brown, Space4 on Mon 1 Oct 2007
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