Novel vegetal-based thermal plasters have been developed, in the framework of a joint research project involving manufacturers and research centers, adopting an integrated multi-objective design process. The adopted methodology, here specifically implemented for vegetal-based hydraulic lime thermal plasters for energy retrofitting purposes, has pointed out the importance of a multi-criteria optimization when studying the development of materials to be used in a retrofitting process, where true sustainability implies that many different aspects need to be tackled contemporarily. The most effective plaster blends have been identified and tested, through an iterative process, which has involved moving from the material/component level to a real building application and taking into account environmental, technological, energy and comfort related issues. (C) 2016 Elsevier B.V. All rights reserved.