The increased use of BIM in the building sector have led certain actors to commence riding on the big data hype. Big data techniques allow the use of unstructured data alongside structured data to an extent that was previously impossible. Science and technology studies (STS) approaches are used to examine information standards as a technology to organise big data applications in building. Crucially, opportunities are strongly guided by the data that is collected about buildings, and thus by the understanding of what a building is. Building information standards are viewed as performative and their becoming as a process of power, understanding and emerging interests. The empirical material stems from a study on the shaping of a Danish classification standard and its implementation in a Danish hospital project. The analysis shows several performative aspects and particular ways in which a building can be understood: First, there is a focus on the internal structure of a building as a product and less on the process that leads to making a product. Second, a systems theory approach to building structure understands building components as having functions in a way that aligns well with the installation part of the building. Third, delimitations within which information standards propose to collect data implies a focus on building components as material over components being economical entities. Performativity struggles during the shaping of the standard are expected to continue also during its implementation phase in an environment where multiple standards co-exist. On this background we discuss whether the building information standard, meant to be a big data technology enabler, might become a barrier for big data.