Technical information

The barrier comprises a concertinaed barrier, encircling the property to be protected. It is made from rigid battens, hinged together, then skinned with a waterproof membrane and attached at the bottom to a housing trench set into the ground, with the top flush with ground level.

The top of the barrier is securely affixed to the underside of a pontoon-like float that extends all around the property as well. The top of the float doubles as the lid for the barrier when in its resting position within the housing trench around the property and is capable of taking the weight of people and vehicles when not in use.

As floodwaters arrive, they fall down into the outer side of the housing trench and start to lift up the float, which in turn starts lifting up the concertina shaped barrier. The whole float and barrier unit acts as the defence against the floodwaters and will continue extending upwards for as high as the flood goes, but no further, all the time using the lifting power of the water itself and no other power.

As the floodwaters recede, so the barrier and float retract slowly back into the housing trench.

At present, 2m homes in England and Wales are at medium to high risk of flooding and 1.7m are likely to lose at least 15% to 20% of their current market value as a result (some may be up to 40%) with this figure likely to rise to 3.6m by the 2080’s (source: RICS report Sept 2004). The current economic damage to the nation is £1.5bn, but this is estimated to rise to £21bn by the 2080’s (Source: "Making Space for Water" DEFRA report 2004).

The Autumn 2000 floods affected over 10,000 properties in the U.K. and cost insurers over £1bn. June and July 2007 proved even more costly, totalling some £3bn. The average cost of each flood claim has risen from £35,000 at the end of last century to between £70,000 to £200,000 per household affected.