Moisture Compatibility of Portland Stones and other Oolitic Limestones

Approximately 30% of Europe's building stock comprises historic buildings, with the UK having a significant contribution of Portland stone structures. However, difficulties in sourcing the original material have led to the need for compatible material substitutes. Currently, the level of compatibility required between original and substitute material has not been quantified, and the approach has been to evaluate each case separately. This research aims to answer the question of how compatible is compatible enough, specifically in relation to moisture risk, and provide a guiding framework for the heritage conservation sector. The project uses a sensitivity analysis to quantify the compatibility of Portland Stone and other Oolitic limestones, considering porosity and age of the original/substitute stone as sensitive parameters when selecting compatible strategies for repair and reconstruction.