General Objective Develop a Profile that defines criteria, steps and procedures to rehabilitate a building with environmental objectives, and that may be used as an assessment tool to achieve a certification for sustainable rehabilitation. Specific Objective Analyze the differences and relationships between the assessment for new constructions and the assessment for existing buildings of each of the defined certifying tools.

A big percentage of the environmental impacts caused by industry come from the construction sector. In Spain almost 30% of the total CO2 emissions come from the use of residential and non-residential buildings. Apart from the energy and water consumption of the operational stage of the building, the resource extraction and material manufacture stages must also be considered, as they represent between 25-30% of the total energy consumption of the building’s life cycle1. Therefore a building as a single body represents a great impact in the environment, the amount of resources consumed and waste produced are excessive and, without any doubt, unsustainable. Under these considerations, this investigation intends to define the rehabilitation of buildings as an answer to address environmental impact. By optimizing management, organization and improving the physical performance of the stock of existing buildings, the rehabilitation with environmental goals embraces the possibilities of transforming the construction sector, by giving way to the concept of re-use and recycle and encouraging these answers in order to recover resources from existing structures instead of extracting them, and improving the buildings operation and management to increase its life cycle performance. But rehabilitating a building is not a simple process. Many factors must be taken into account especially when the building is operating. Certifying tools for sustainable buildings give the guidance, through a list of criteria, to accomplish a level of sustainable efficiency in the building, for either new construction or existing buildings. The certifying tools for existing buildings have been developed to assess their current performance in operation and maintenance, and the potential they have to improve. The certifying tool for new constructions guides the building from the design stage to the construction stage to accomplish a physical and inherit sustainable performance. By analyzing and comparing both types of assessment tools and from different organizations (LEED and BREEAM), it is intended with this work to develop a tool that will not only certify a rehabilitated building, but will also shows the steps, the criteria and procedures for a Sustainable Rehabilitation.