This paper describes a tool to assess building sustainability on micro and small building firms. In recent years occurred great transformations in design and management phases of buildings. Sustainability is very important because the environmental impact of building sector. The application of innovations generally occurs only in mid or large building companies, however the micro and small building companies represent the majority of the companies. We proposed a tool adjusted to smaller context. Using a sample of buildings, the tool demonstrated be adequate, because it is comprehensible and useful to users with different level of education and knowledge about sustainability.