Hot Lime Mortar in Conservation—Repair and Replastering of the Façades of Läckö Castle

Slaking quick lime directly with sand produces ‘hot lime’ and ‘hot lime mortars’. The repair and conservation of the façades of Läckö Castle in western Sweden is a rare example of this method being used in conservation practice. The objective of the Läckö project has been to develop a repair mortar that is technically compatible with those used in the original structure. The hypothesis is that hot lime could provide the key to replicating the qualities of the original lime-rich, historic mortars and would thus be suitable for making compatible mortars. This paper is an account of the experience and describes the processes of burning lime and slaking and the production and application of ‘hot-lime’ mortar. It also considers the properties and advantages and disadvantages of hot lime mortar compared with those of traditionally ‘wet-slaked mortar’. The experience so far has been encouraging.