This article analyses the micro‐level rule enactment of the posting of workers framework in the German construction sector. I examine how actors draw on different power resources in order to influence policies without formal negotiation within transnational workspaces and thereby initiate institutional change. Drawing on interviews with posted workers, managers, unionists, works councillors and labour inspectors I show how transnational subcontracting allows the emergence of different regulatory spaces at national and workplace level. The article concludes that the informal renegotiation of employment relations in transnational workspaces is likely to destabilize the posting framework negotiated at policy level.