Purpose – Sustainability is well understood to encapsulate economic, environmental and societal parameters. The efficiency of maintenance interventions for historic buildings is no exception and also conforms to these broad factors. Recently, environmental considerations for masonry repair have become increasingly important and this work supports this growing area. The purpose of this paper is to give insight on how an option appraisal approach of “Green Maintenance” modelling for historic masonry buildings repair practically determine and ultimately substantiate the decision-making process using a calculation procedures of life cycle assessment, within delineated boundaries. Design/methodology/approach – Calculation procedures of the model enables an assessment of embodied carbon that is expended from different stone masonry wall repair techniques and scenarios for historic masonry buildings during the maintenance phase. Findings – It recognises the importance roles Green Maintenance model can play in reducing carbon emissions and underpins rational decision making for repair selection. Practical implications – It must be emphasised that the calculation procedures presented here, is not confined to historic masonry buildings and can be applied to any repair types and building form. The decisions made as a result of the utilisation of this model practically support environmentally focused conservation decisions. Social implications – The implementation of the model highlights the efficacy of repairs that may be adopted. Originality/value – The paper is a rigorous application and testing of the Green Maintenance model. The model relays the “true” carbon cost of repairs contextualised within the longevity of the materials and its embodied carbon that consequently allows rational appraisal of repair and maintenance options.