New Eco-friendly foundation speeds construction Monday, 10th November 2008
‘SystemFirst’ is an innovative foundation that combines galvanised steel beams and high density polystyrene to create a strong, sustainable, lightweight and highly insulated floor slab.
More than 150 delegates from across the building sector attended an opening day and demonstration event at RBL’s head office and manufacturing facility near Burton-upon-Trent, Staffordshire in July. A building plot had earlier been prepared with a support system and caps installed in the ground, before the demonstration took place to show how quickly and simply SystemFirst can be pieced together.
RBL Director John Patch says: “Our sustainable foundation system can help developers to achieve Sustainable Home Code 6 – which means a building is completely carbon neutral. Use of SystemFirst on its own will not be enough to reach Code 6 for a whole building. But coupled with other systems, such as geothermal heating and use of renewables like solar energy, it is possible to achieve this target.”
Prefabricated steel beams are manufactured off site and sheets of polystyrene insulation are cut to size. Both are clearly labelled in line with construction drawings before being delivered.
Laying the SystemFirst foundation is like putting together a large puzzle. It took a team of just three people to lay the foundation at the demonstration, positioning each piece by matching the labels according to the drawings. The labeling also enables easy identification if a piece is damaged.
The first sections to be laid were the steel ground beams containing service ducts, which are secured on to the concrete pile caps, spaced at 3.5m centres for the purposes of the demonstration. Steel reinforcing bars are then added to the ground beams to give added support to the foundation.
Each polystyrene panel, complete with cold rolled steel edging, is designed to be lightweight and requires no more than two people to lift it. Use of the material also removes the need to use heavy lifting equipment. Three versions of floor panel, each with either one, two or three layers of polystyrene can be specified, depending on the insulation requirements required.
Once the floor panels are in place, another layer of thin polystyrene is added on top, followed by installation of a polystyrene ‘thermal break’. Specialist magnetic steel brackets were used to secure temporary shuttering in place, before RBL’s self compacting and self levelling concrete was poured to create a solid base and complete the foundation.
SystemFirst is a very versatile foundation. RBL’s John Patch said: “This system can be used for a single dwelling or a commercial foundation, irrespective of the number and variety of the buildings. Depending on the size of each plot, a team of three people can lay the foundations for about three or four buildings each day.”
Improved safety is one of many benefits of specifying SystemFirst over traditional foundation construction. There are no heavy lifting equipment, machines or plant needed on site while the foundation is put together as each piece can be lifted, carried and fixed in place by hand. No cutting equipment is required as all of the pieces are cut to size in the factory before being delivered to site. Use of prefabricated materials reduces waste and associated lorry movements.
Emissions created by producing large volumes of concrete for traditional foundations are also greatly reduced by specifying SystemFirst, making it a much more environmentally friendly method of construction.
An early use of SystemFirst was completed last year, when the foundation was installed for a bespoke bungalow built in Chatham, Kent, which was profiled for the Grand Designs television programme. For this project, a total of 20 different lengths of the foundation were laid by hand.
“SystemFirst has huge possibilities,” said RBL Chief Engineer Nigel Rake. “At the moment it is being used for building houses, but there is no reason why it cannot be used for building other much larger structures such as schools or offices. Our own two storey office was built on a SystemFirst foundation.
“We have carried out a lot of research into the system to find its true benefits, but the differences with conventional methods of installing a foundation were more significant than we had expected,” he added. In a comparison between SystemFirst and a traditional trench fill foundation method for the same floor area, SystemFirst created 12.7 tonnes of CO2 compared to 72.9 tonnes with the traditional method. The new system also used 4287 litres of water during construction compared 36,026 litres for the traditional method. In terms of materials used, a typical SystemFirst foundation uses 18 tonnes of concrete compared to 233 tonnes used in the trench fill.
At the demonstration day, John Patch concluded: “If we, as a nation, adopt the sort of construction methods we have seen today we will all see substantial savings in emissions and the environment.”
