The considerable amount of energy spent on the construction, maintenance, and demolition of buildings draws attention to sustainable development in the construction sector. Regarded as both tools and frameworks, laws are expected to sustain and speed technological innovation. With the STS (Science and Technology Studies) theory of domestication and in-depth interviews with building researchers studying zero emission buildings in Norway, I discuss the role of research engineers in the domestication of law, that is, the translation of European Directives for building codes and technical requirements, and the mediation of these legal frameworks for industry and practitioners. I classify two main and opposing ways of domesticating the law in ‘inside-the-box’ and ‘outside-the-box’ approaches. The domestication of law accounts for numerous aspects and thus simultaneously becomes a technological, cultural, political and legislative activity. The paper contributes to a better understanding of the legislative roles of research engineers.