If you have a mortgage yes you will require building insurance and even if you don't it should be
a priority in case the worst happens.Buildings Insurance will normally cover you for fire,earthquakes (yes they do happen
in UK) damage,aircraft damage,trees,explosions etc.
The buildings
insurance you choose should cover the financial costs of rebuilding and this cost should also cover the costs in the worst
case scenario of flattening the property and clearing the site.