Barrett Byrd Associates

Stainless steel house foundations are set to mount a challenge to conventional supports formed using trenches filled with concrete, reports Mike Walter

Concern over disposal of spoil from sites reserved for new housing has driven development of a new foundation system made from lightweight stainless steel. The foundation is known as ‘SystemFirst’ and features a grid of stainless steel beams, assembled on site to form a secure base from which two storey houses can be built.

Use of SystemFirst does not require a trench to be dug and filled with concrete around the perimeter of a house. Potentially contaminated spoil on brownfield land, therefore, need not be disturbed or disposed off site.

Instead, the stainless steel frame is supported by a series of precast concrete piles or vertical columns of compacted concrete that firm the ground by displacing material laterally, bringing no material to the surface. Galvanised steel channels are used as floor joists and are supported by the foundation beams.

SystemFirst has been developed by the foundation specialist Roger Bullivant Ltd (RBL), which secured approval for use of the product this spring from technical standards body the British Board of Agrément. RBL’s national sales manager Andy Preece says that pressures on waste disposal are set to make the new foundation system attractive for housing developers.

“Ground workers who dig foundation trenches around housing plots and fill them with concrete create a phenomenal amount of spoil and the charges associated with transporting material and disposing of it at landfill can be horrendous,” he says. “Costs can rise even further if the ground contains a contaminant and many landfill sites will not accept material of a variable quality.”

Installation of a SystemFirst foundation for a small terrace of five houses requires only one truck to bring lengths of stainless steel to site. Two operatives can lift a section of beam by hand and slot numbered pieces into place by following a detailed design drawing.

Four combinations of shaped beam have been developed to spread load; external and internal support beams are complimented by a third detail to support a separating wall and a stepped beam can provide support for a garage threshold. Steel sections are cut to predetermined lengths before arriving on site and external beams are designed to span between and be secured to concrete pile caps. Panels of expanded polystyrene are then lowered into place between steel beams to provide an acoustic barrier and heat insulation, before a 40mm fibre reinforced concrete screed is poured and levelled. Installation of the foundation can then be followed by the building of either a brickwork and blockwork construction, timber frame or steel frame structure.

“The purpose of SystemFirst is to compete with traditional house foundation methods on ground that does not require extensive treatment,” adds Preece. “Installation of the foundation is quick and the environmental impact of building a house is reduced as there is no need to dig and dispose of spoil.”

SystemFirst’s inaugural outing took place earlier this year as a trial on a small residential development at Mickleover near Derby. A second contract followed this summer at Buckshaw Village in Lancashire, a housing development on the 160ha site of a former Royal Ordnance factory which manufactured artillery during the Cold War. Buckshaw Village is currently one of the North West of England’s largest brownfield regeneration schemes.

Two thousand properties are being built on the site by a selection of house builders including Barratt Homes, which is trialing use of the SystemFirst foundation to support a terrace of five modular steel framed houses. The terrace is being fabricated off site – in much the same way as the foundation – in order to reduce construction time on site and to ensure a consistently high quality finish.

Technical director Graham Swann from Barratt Manchester says: “The system of house building we have chosen at Buckshaw Village is known as Advance Housing. Steel frame wall panels, complete with insulation and plaster board, are manufactured in a factory, brought to site and bolted together and secured to the steel foundation.”

Door and window openings are pre cut into the panels before they arrive on site and an outer layer of brick completes the shell of the house. Fully fitted kitchen and bathroom units are manufactured in the factory, and sealed before being brought to site and lowered into place.

The terrace of five houses built on the new foundation at Buckshaw Village was completed in October. Andy Preece from RBL adds that housebuilders around the county are showing a healthy interest in SystemFirst and further contracts using the house foundation system are likely soon.

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