Recent work on building stone decay focuses on exploring the response of stone to various weathering phenomena, including salt spray and freeze-thaw cycles, and issues surrounding compatibility of replacement materials. Yet, that same body of work generally ignores the contribution of mortar composition and characteristics to observed decay processes – despite the intimate relationship between mortar and stone in historic masonry structures.

My PhD research project, within the Geomaterials Research Group, seeks to address this knowledge gap by investigating the weathering of conservation mortars and the surrounding stone substrate through a two-pronged approach: fieldwork and laboratory experimentation. The fieldwork provides observations of real-world responses to natural weathering of stone masonry structures, while the laboratory work offers a controlled situation to analyse degrees to which specific events impact weathering behaviour of conservation mortars and their stone substrates.

The laboratory work centers around artificial weathering of specimens constructed using local Dungannon sandstone and three mix designs representative of general conservation mortars. After curing, the lab specimens are artificially weathered through various combinations of environmental factors (diurnal temperature variations, salt spray, freeze/thaw cycles) and one-off events (fire, replicated using a furnace) to study the impact of complex stress histories on conservation mortars and their surrounding stone substrate. The results will then be compared to field observations collected from six EHS-managed historic sites in Northern Ireland, of similar age and selected to represent coastal, near-coastal, and inland aspects of sandstone weathering.

By investigating the response of historic and conservation mortars to a variety of weathering processes, this research facilitates improved understanding of mortar-related decay mechanisms in historic stone structures as well as providing a basis to predict future deterioration patterns in light of climate change. Such knowledge and understanding can have a global impact on historic conservation, improving our ability to successfully preserve our architectural and cultural heritage for future generations.

Dotter, K.R. (2010) “Historic lime mortars: potential effects of local climate on the evolution of binder morphology and composition.” In Limestone in the Built Environment: Present Day Challenge for Preservation of the Past, Special Publication 331. London: Geological Society of London, p. 119-126.

Curran, J., Warke, P., Stelfox, D., Smith, B., and Savage, J. (2010) Stone by Stone - a Guide to Building Stone in the Northern Ireland Environment. Contributor. Belfast: Appletree Press, 317 pp.

Dotter, K.R., Smith, B.J., McAlister, J., and Curran, J. (2009) "Sacrifice and rebirth: the history of lime mortar in the north of Ireland." In Proceedings of the 3rd International Congress on Construction History, 20-24 May 2009, Cottbus, Germany. Cottbus: Brandenburg University of Technology, p. 499-506.

Dotter, K.R., Smith, B.J., McAlister, J., and Curran, J. (2008) "Effects of weathering processes on conservation mortars and the surrounding stone substrate." In Proceedings of the 11th International Congress on Deterioration and Conservation of Stone, 15-20 September 2008, Toruń, Poland. Toruń: Nicolaus Copernicus University Press, p. 57-64.

Dotter, K.R. (2007) “Symbolism of Stone Use in Traditional Chinese Gardens.” STONE:    Newsletter on Stone Decay, No. 3.

 Presentations

Dotter, K.R. (2009) “Sacrifice and rebirth: the history of lime mortar in the north of Ireland.” Presented at the 3^rd International  Congress on Construction History in Cottbus, Germany, 20-24 May 2009.

Dotter, K.R. and Smith, B.J. (2008) “40 years of conservation mortars: evolution and effects.” Presented at the Association for Preservation Technology conference in Montréal, Québec, Canada, 13-17 October 2008.

Dotter, K.R., Smith, B.J., McAlister, J., and Curran, J. (2008) “Effects of weathering processes on conservation mortars and the surrounding stone substrate.” Presented at the 11^th International Congress on Deterioration and Conservation of Stone in Toruń, Poland, 15-20 September 2008.

Dotter, K.R. (2007) “Historic lime mortars: potential effects of local climate on the evolution of binder morphology and composition.” Presented at the Stone Weathering and Pollution Network (SWAPNet) conference in Valletta, Malta, 24-26 May 2007.

Dotter, K.R. (2006) “Historical and current analysis methodologies for the characterization of historic lime mortars.” Presented at the AIC Annual Conference in Providence, Rhode Island, USA, 16-19 June 2006.

Dotter, K.R. (2005) “Characterization and comparison of modern and historic lime mortars.” Presented at the APT Annual Conference, Halifax, Nova Scotia, Canada, 21-26 September 2005.

Dotter, K.R. (2004) “Early 20^th century prison technology.” Presented at the APT Annual Conference, Galveston, Texas, USA, 4-7 November 2004.

Dotter, K.R. (2003) “Air Pollution and Stone Consolidant Study.” Presented at the NCPTT Summer Public Outreach Lecture, Natchitoches, Louisiana, USA.