The field of valuation of the professionals is developed mainly the free market that comes regulation by the norm ECO 805/2003, the administrative valuations and especially in the expropriation is governed by state and autonomic laws and regulations that are increasingly closer to the market valuations, but taking into account that value must be given and a price determined in soils destined to systems without assigned buildability, it should be defined, if it has not been delimited by a specific urban planning, a homogeneous spatial area that allows establishing a correct weighted buildability for the concrete floor to be evaluated. Define the value of the soil (residual method) or built-up roof (comparison method) to be obtained from reliable data according to the requirements of the specific regulation.