Flood risk sites should be no barrier to development

Risk of flooding should not necessarily rule out development of otherwise attractive potential building sites, an expert in foundation engineering has claimed.

Director of piling specialist Roger Bullivant John Patch said that flood risk can be managed for new dwellings, in particular by choosing the right foundations.

Speaking at Civils 2007 last month he said that pressure to build many thousands of new dwellings in the UK over the next 15 years will mean areas prone to flooding cannot be overlooked.

"There is absolutely no insurmountable problem in building on flood prone sites, as long as we deal with the risk accordingly," Patch said.  

"There are procedures in place to accommodate development in low lying areas and it is now up to the construction industry to recognise that."

He explained that houses built in flood risk areas can be supported on foundations raised clear off the ground. Foundations are suspended on a series of precast concrete or displacement piles that firm the ground without bringing material to the surface.

House foundations suited to flood risk areas include RBL's lightweight galvanised steel foundation support product SystemFirst. Perimeter and floor beams are produced at the company's manufacturing facility in Staffordshire and installed by hand on site. Pre cut insulation panels are then dropped horizontally into place between the floor beams, before a screed of concrete is laid in situ.

Each beam spans a pair of precast concrete pile caps, with each cap supported by a foundation pile. These piles can be formed either of precast concrete sections or a cast in situ column created using the continuous helical displacement technique.

Patch added that use of prefabricated materials is suited to developments in flood risk areas, because they can be installed quickly using lightweight equipment that does not exert undue stress on the ground. An RBL rig weighing less than 25t and sat on tracked footings can be manoeuvred easily and operate safely on ground that may be soft, he said.