There has recently been a growing interest for ethnographic studies in construction, predicated upon the belief that ethnographic research in the construction industry can provide a powerful way of illuminating construction practices in new ways. Focusing on the ethnographic method, it is demonstrated how a self-reflexive ethnography can contribute to a deeper understanding of the variations, contradictions and tensions underlying practices on a building site, thereby serving as a complement to other qualitative approaches. A short four-week ethnographic study illustrates how the subjective "I" of the ethnographer can be used as an active producer of knowledge, by reflecting on how insights from an individual´s role, both as an observer and as a worker, can account for the complex interplay between socialities and materialities on a building site. The results also contribute to the discussion regarding the length of ethnographic studies, by showing how valuable insights can be drawn from shorter "ethnographic episodes", studied through a self-reflexive lens.