This is of personal importance to me so I did some research. There is a difference between liability (and types of insurance-cover available/necessary) for 'a vacant property' as opposed to 'a property in process of renovation'. In the latter case, foundations, skeleton of utility services including access roads, already exist.......otherwise it could not be classified as 'a dwelling', regardless of age or condition. This is distinct from both a property being newly-constructed (a building site) or a property which has no-one currently living in it, or where the owner is absent for more than the period specified by the home insurance policy.