Journal of Architectural Conservation
Volume 17, Issue 1, March 2011
Hot Lime Mortar in Conservation - Repair and Replastering of the Facades of Lacko Castle
Ewa Sandstrom Malinowski and Torben Seir Hansen
Paper Summary
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 was to develop a repair mortar that was technically compatible with those used in the original structure. The hypothesis was 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 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.
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Figure 21 Thin section with different binder related particles (‘wet mortar’, lime/sand ratio 1:2). K=Lime inclusions, Kh=particles with hydraulic components, C=particles of incompletely burned lime, Gips= gypsum. Black fields= air pores (T. Seir Hansen).
Figure 22 Thin section showing binder, B, (‘wet mortar’, lime/sand ratio 1:1) with a particle with hydraulic components, Kh . Needle-like crystals, CAH, are formed on the surface through hydraulic reaction with water. Yellow field= air pore (T. Seir Hansen).
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Ewa Sandström Malinowski, PhD.
Ewa Sandström Malinowski is an architect and senior lecturer and researcher at the Department of Conservation, University of Gothenburg, Sweden. Her main area of interest is the use of traditional materials and crafts in architectural conservation, in particular in the conservation of lime plasters. She coordinated the ‘Historic Mortars at Läckö Castle’ research project.
Torben Seir Hansen
Torben Seir Hansen is the owner and managing director of SEIR-materialeanalyse A/S, located in Elsinore, Denmark. The company specializes on laboratory analyses and consults on concrete, plaster, lime mortar, masonry, natural stone and surface coatings.
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