This paper describes a process used to develop and test a framework to produce thermal simulation post-processed information meaningful to building design decision-making. The framework adopts a user-centred approach in which the building designer is considered the ultimate simulation tool user either directly or indirectly when supported by consultants. The framework supports the building designer's ‘modus operandi’ and is developed through a set of interdisciplinary research methods. Participatory Action Research, Thematic Analysis and Grounded Theory are used, together with principles from Information Visualization, dynamic thermal modelling and Building Design, following a design approach to problem-solving taken from the discipline of Interaction Design. The various elements of the framework and their connections are derived from analysis of sequences of design actions made by novice designers undertaking complex design activities. Tests of the framework are undertaken through an online questionnaire and five semi-structured interviews with UK architectural design practices.