A building stone audit for Kilmarnock : surveying, matching, and sourcing stone for the built heritage

Surveys of the condition of the stone masonry in twenty-five buildings and structures in the John Finnie and Bank Street Conservation Area in Kilmarnock have provided information to guide forthcoming grant-aided repairs and inform future maintenance strategies. Stone samples from each surveyed structure have been characterised in order to identify the original stone types, and are matched to stone from currently active quarries to ensure that appropriate stone is used for the repairs. Kilmarnock’s historic stone buildings directly reflect the local geology, providing a strong ‘sense of place’. The changing use of stone through time has contributed to the evolution of architectural styles that document different stages in the town’s history. The earliest buildings and structures used locally-sourced blonde sandstone with whinstone, probably obtained from nearby surface outcrops and boulders. Subsequently, better quality blonde sandstone was obtained from several town quarries, notably Dean Quarry which provided large quantities of stone in the first half of the 19th century. Once connected to the wider railway network, red sandstone was imported from the Mauchline area, providing higher quality stone that enabled a more ambitious architecture in the second half of the 19th century, reflecting the increasing prosperity of the town. Although red sandstone dominated from this time, a few notable buildings used imported blonde freestone for high quality ashlar and decorative work. The condition surveys show that the principal reason for damage to stone is water penetration, leading to surface soiling (biogenic growth) and scaling of the masonry surface. A major cause of water penetration is lack of maintenance, in particular failing rainwater goods. Much of the damage is associated with exposed and projecting masonry elements such as cornices, string courses and sills, which require repair or replacement in order to protect the adjacent masonry and ensure long-term survival of the stonework. The use of de-icing salts on roads and pavements has caused considerable salt contamination to masonry at ground level resulting in disaggregation of stone. Damage due to previous stonecleaning has caused loss of masonry details, significantly degrading the appearance of several buildings. Today all of the original stone quarries that supplied Kilmarnock are closed. Petrographic analysis of the masonry samples has identified the closest matching stone types from currently available quarries throughout the UK. The best way of ensuring compatible stone is to reopen the original quarries. Most of the original quarry sites cannot be reopened, so areas of adjacent geology have been identified which could provide sites for the renewed production of stone. The results from this study are intended to guide the repair of masonry and ensure that appropriate replacement stone is selected for repairs, as well as highlighting the importance of maintenance. This information is relevant to other buildings in Kilmarnock and the surrounding district, as well as the wider Central Scotland area. The reopening of stone quarries would provide a sustainable source of appropriate stone to ensure the conservation of the built heritage in Kilmarnock and East Ayrshire.