Could this house be the answer to building on flood plains?
Larkfleet is developing a flood house which jacks itself up to save it from damage. This novel solution to flood risk is one of several being considered to enable developers to build on marginal land across the UK
Report from – Michael Hardware
Image courtesy of Larkfleet
Unlike previous years, there has not been serious flooding in the UK last winter. This may be more of an exception than a return to the norm as more flooding events are certainly expected in the future with the onset of global warming, and the incidents are expected to become more-and-more extreme.
The UK also has an ever-growing population, and subsequent housing need. This has led to a housing crisis which has now been in existence for several decades. All previous attempts to resolve it have failed with all the main political parties now advocating more house building, with the Conservatives wedded to the policy of delivering a million new homes by 2020. There is significant pressure on scarce land, especially in the south east. This has led developers to look more closely at ‘marginal’ land, which has an increased risk of flooding, especially in urban areas.
Larkfleet has come up with a novel solution to building on this marginal land: a house which actually rises up above the flood. It has been granted planning permission by South Holland District Council to build a prototype in Weston Hills, near Spalding, Lincolnshire. The three-bedroom detached property will be capable of being raised 1.5 metres on eight mechanical jacks powered by a central motor, gear box and drive shafts, in approximately five minutes. If the testing is successful, it could provide a solution to allow development on thousands of flood zone sites around the country.
The 65-tonne prototype house will be of modular steel frame construction and will sit on a steel beam in place of traditional foundations. Experiments with raising and lowering the house – including testing long-term maintenance and operation of the jacking system – will run for up to five years. When the tests are complete, the house will be disassembled and re-built on another site on conventional foundations as a family residence.
It is anticipated that the house will be jacked-up in advance of a flood, based on warnings from the Environment Agency. Residents are expected to pack up, lock up and jack up the home before taking refuge in temporary accommodation on higher ground elsewhere, although not necessarily.
“There are a number of practical aspects of the flood house to be resolved,” said Karl Hick, CEO of Larkfleet, “which will be helped by the prototype house and five-year test.
“Electricity, sewage and water, and health and safety are key issues to be considered, especially with the possibility of residents remaining in occupation during the flooding.”
Services can remain connected via flexible hoses and wires, but what if the power fails? Although the solar panels on the roof and a battery will provide some power, a generator may be incorporated to facilitate full habitation, and jacking-up the house if a flash flood cuts power. Other aspects to be considered include access to the building and what to do about debris under the house.
“We are taking our time over the design of the flood house,” added Hick, “and even longer over the testing of the concept once the prototype house has been completed, expected later this year.”
Image courtesy of Larkfleet
Larkfleet is working with BRE near Watford to test the technology. John O’Brien, associate director at BRE, is leading the team. He said: “This is an interesting concept which is one of many being developed to increase flood resilience across the country. Building in flood zones 1 and 2, with flooding risks of one in 1000 or 100 years respectively, could be considered acceptable if proper mitigation measures are in place. We will need a combination of solutions in our toolbox so that we have flexibility to address the different risks around the country, including not just river flooding but groundwater flooding as well.
“Larkfleet have a number of practicalities to overcome with its elevating home concept, and the test home in Lincolnshire will enable it to do that. BRE will be looking at the concept overall including the jacking system, utilities and heating, as a lack of services could lead to hyperthermia.”
O’Brien agrees that housing demand is pushing developers and local planning authorities to look more closely at the land available: “With huge pressures to build more homes, land with flood risks is being considered more-and-more, especially in towns and cities in the south east.”
“This is not a panacea for our housing crisis,” said Hick, “it is one solution which may help to improve flood resilience, one of many different approaches that could be adopted, allowing development on sites not previously possible.
“There is a price premium, to cover the additional construction costs, but this should be offset by the reduced land value, and over time, as volumes increase, that premium will fall.
“There is also maintenance cost for the duration of the life of the home, even if there is never a need to jack-up the house for a flood.”
Insurance companies have been hit hard in recent floods, and are understandably very wary of new approaches to building in flood risk areas. Similarly, mortgage companies would need to get comfortable with the approach, as would the National House Building Council, which provides warranties on new homes, crucial for purchaser confidence.
Larkfleet has confidence in the approach: it has applications lodged for UK and international patents for the ‘elevating house’ and these are pending.
“The Lea Valley and Thames Gateway both have extensive flood plains with large amounts of disused industrial land within them,” added John O’Brien. “These have been identified for residential development.
“It is likely that, initially, it will be housing association and private rental sectors which go down this path.”