Different levels of sustainability in building design: recognising a codified process

Implementing sustainability criteria in building design is not a codified process although some technical solutions seem to be essential, various assessment tools are available, and laws and regulations force or suggest best practices. This is mainly due to two factors: one is the subjectivity related to the design activity; the other is the uncertainty strictly related to the sustainability concept. Designing is an iterative process, aiming at reaching the most satisfactory solution, based on knowledge and expertise of designers; integrating sustainability in the process requires using a sustainability related knowledge which is continuously evolving. This paper is a reflection on which features of the building design activity seem to guarantee a sustainable behaviour of construction and the built environment better, in order to understand if a codified design process can be recognised. Based on some building projects developed for engineering graduation theses, different levels of sustainable solutions are considered, from a single building to a building complex, from new constructions to old buildings subjected to a renovation and re-functioning design. Having a codified design process as a reference frame can help to teach students and train professionals, as well as implement design support tools.