In technical problems where decisions must simultaneously satisfy several conflicting objectives, methods are based on benefit-cost analysis or multicriteria decision analysis helpful to identify the “optimal” decision. Usually big technical decisions are made by politics and influence the environment, but specialists, constructors and the society must have the ability to overview and inspect these decisions. In the theory of economics, the level of financial growth is used as an indicator for assessing social prosperity. However, the growth rate might be accompanied by unfavorable effects on the social community’s prosperity. Such negative effects are for instance the danger against public health lying in the environmental pollution, the dangerous shrinking of biodiversity and the exhaustion of natural resources. Within this context, the concept of the environmental preservation has been developed, i.e. the long-term preservation of the ecosystem’s viability, as well as the concept of sustainability, that is covering present needs but not to the detriment of future needs. It has been observed that society develops a discerning ability on technological applications (hence an ecological predisposition) when it reaches such a stage of maturity where it comes up against the pollutants it produces itself. This phenomenon, as it is described in Environmental Psychology, is “as if you’re waiting for a building to catch fire in order to study the new safety rules regarding buildings’ fires’’. It continues then, “it is rather immoral to wait for a building to catch fire so that you’re given the criteria on how to study the new safety rules regarding buildings’ fires’’. (Cander, 1988). A building, is a creation of humans which affects both the environment and humans themselves. A building might negatively affect humans and the environment during its construction and operation stages or can emerge as spoilage after its use. For this reason, different criteria arise to define the building’s ecological behavior so that the positive effect is maximized and the possible unfavorable effects to humans and the natural ecosystem are minimized. Extensive analysis of the problem from several viewpoints and a presentation of the reasoning are necessary to achieve an informed decision based on understanding and knowledge. In order to optimize a technical decision for society, engineers, experts and politics, architecture of a web platform based in "common" knowledge, optimizes the decision making analysis by evaluating building materials based on ecological criteria.