VicUrban, the Victorian state government urban land development agency, is showcasing its sustainability credentials in their new 8000 home Aurora Estate. Aurora will have environmental features which, amongst other initiatives, require the use of materials that are more environmentally sustainable. The EcoSelector was designed to guide the builders in their selection of materials. More or less points are allocated depending on the materials used for the floor structure, framing, wall cladding, roof cladding, fittings and finishes, and landscaping. The builders are required to meet a minimum overall score for a proposed house before it can be approved by VicUrban. The relationship between VicUrban and the builders is critical for VicUrban to succeed in delivering environmental sustainable design (ESD). Cost pressures play a significant role and the people on the ground, often sub-contractors, have little incentive to do any research or development into issues like sustainability. Against this background, the development of the EcoSelector can be seen as an innovation grappling with the market driven limitations of the industry whilst promoting ESD. VicUrban hopes to transform the building industry via demonstration. This paper examines how the relationships between the participants affected the development of the EcoSelector and how this has affected the building industry. As a part of work in progress, a new model is suggested for understanding the relationship between innovation, agency, and structure that ranges across 'silos', drawing on Vygotsky's (1978) developmental psychology, Wittgenstein's (1958) philosophical insights, Bourdieu's (1977) concept of habitus, and evolutionary theory. 1 is a building and landscaping materials selection tool that was developed specifically by the Victorian State Government's land development agency, VicUrban, for their Aurora Estate. Aurora is a staged development, due for completion in 2023, which on completion will comprise 8000 houses. Aurora is VicUrban's sustainability 'showcase'. They define sustainability broadly, having adopted and developed a triple bottom line policy framework. This framework is articulated through VicUrban's Sustainability Charter (VicUrban 2006) which is used to evaluate proposals, design projects, and measure the performance of their developments. The EcoSelector dovetails with the Sustainability Charter addressing the specific issue of the impact of building materials on the environment. The EcoSelector was designed specifically for the Aurora project to provide the builders with information about; the environmental benefits of more sustainable building materials, where to source them, and whether there was a cost difference. The EcoSelector can be seen to address two related phenomena; the way builders think about sustainability and, how they do it, that is the acts and practices of building. Indeed, it is evident in the story of the development of the EcoSelector, described in this paper, that the resolution of these two purposes of the tool, as a means of consciousness raising and/or as a means of changing practice, helped shape how the tool was intended to be used and the manner in which the builders have had to comply to it. The issue concerning the purpose of the EcoSelector, as were other issues discussed by its developers, took place within a particular context that afforded particular constraints and opportunities. These resistances and encouragements define both the 'problems' that the EcoSelector designers sought to address as well as the scope or level of innovation that could be achieved. The constraints included dealing with an industry that is driven by neo-liberal assumptions regarding the operation of markets and consumer choice, as well as being defined by economic pressures that are resolved through Fordist manufacturing and assembling processes. Furthermore, sub-contractual relations