Material properties of building limes for pointing mortar for renovation and restoration of neo-Gothic churches in Sweden

¹ Division of Building Materials, Department of Building & Environmental Technology, Lund University, 221 00 Lund, Sweden
² Conservation, Uppsala University Campus Gotland, 621 57 Visby, Sweden

^* Corresponding author: kristin.balksten@konstvet.uu.se

Abstract

During the neo-Gothic period of the 18th and 19th century, many churches in Sweden were built in brick and natural stone with a traditional lime-based mortar. Moisture- and salt related problems were common in these church buildings, already a few years after they were erected durability problems arose. Examples of these durability problems were internal salt precipitation, leaching of lime-based mortar and other moisture-related deterioration of mortar joints. When these neo-Gothic churches are repointed, this should be done with appropriate traditional lime mortars. However, since the introduction of cement as a material for mortars and renders, the knowledge on lime-based mortars has gradually decreased. Lime as a material for mortar, renders and plasters is still used, but only on a small scale and mostly for work on heritage buildings. There is a knowledge gap regarding material properties and workability of traditional limes. Therefore, the aim of this project was to determine the material properties of lime mortars used for restoration of churches built in brick or natural stone masonry.