Background: We are experiencing a period of climate change the extent and impact of which is uncertain. In the cultural heritage sector the need for monitoring to inform our understanding is widely agreed, yet there is a lack of consensus over what constitutes 'monitoring for climate change'. This is due, at least in part, to the extended time-scales involved. In this paper the design and implementation of one solution is described; a sustainable legacy indicator tool (LegIT) for the long term tracking of surface weathering effects on built heritage. Results: The assessment of climate change impacts requires 30-100 years of data collection, equal to the period referred to as the 'climate norm' by meteorologists. The LegIT is a sacrificial stone object that registers changes in the severity and/or magnitude of weathering patterns on built surfaces, providing a legacy data source for future decision makers. To ensure its sustainability, careful thought was given to the choice of materials, data retrieval and archiving. The tool aims to track surface changes caused by recession, salt crystallisation and microbiological growth. Conclusion: The development and installation of the LegIT is the first long-term exposure trial to be initiated at heritage sites in Ireland and is intended as a legacy for future researchers.
