Norwich Union (NU) is to extend its risk mapping capability to cover subsidence and wind damage.

The insurer plans to use the technological know-how built up through its flood-mapping programme to hone property premiums by taking into account other risks.

By overlaying data such as soil type and wind velocity on the existing map, analysts at NU believe they can generate more accurate premiums.

An NU spokesperson said: "It would be a wasted opportunity if we did not develop the map for other areas. We hope to move from flood mapping to subsidence and wind damage this year."

Though water damage more often captures the headlines, the cost of either subsidence or wind damage can easily outstrip flooding on an annual basis.

ABI figures for 2002 put subsidence costs at £183m, storm damage, including an element of water related costs, at £469m and flood damage at £131m.

The need for accurate underwriting in both subsidence and wind damage has been highlighted by last year's long hot summer driving up subsidence claims, and the long term predictions of a 6% to 10% increase in wind speeds.

NU's flood map is due to go live this spring.