The project will provide practical decision support tools that will enable practicing designers to systematically assess alternative low impact design options against carbon emissions, time, cost and waste performance measures simultaneously. This area has been chosen as it is central to realising low impact buildings and the consideration of carbon emissions and waste along with the multiple performance measures currently present significant challenges to designers. The current proliferation and sometimes absence of tools are not adequate as they address the problem in a piecemeal fashion, do not interoperate, most are not easy to use and do not allow a holistic assessment to be made. The work will focus on: establishing methods, protocols, and rules for measuring embodied carbon emissions and waste from construction materials, components, and activities; establishing cost and waste drivers and methods of estimating project time and costs of designs that incorporate innovations in low impact and sustainable building technologies and methods at the early stages of the design process; developing integrated models for estimating carbon emissions, waste, time and costs simultaneously; leveraging emerging Building Information Modelling (BIM) technology to develop easy to use interoperable decision support software components that implement the methods and models developed; testing and validating the methods and software tools on selected case studies; and establishing mechanisms for exploitation and wider dissemination of the results. The use of integrated models that can handle the natural correlations between material quantities, emissions, time, and cost is innovative.