Towards an on-site mortar archaeology of the Isle of Lewis

Citation

Thacker M (2012) Towards an on-site mortar archaeology of the Isle of Lewis. Journal of the Building Limes Forum, 19, pp. 38-44. https://www.buildinglimesforum.org.uk/wp-content/uploads/2017/07/Contents2012BLFJournalVol19.pdf

Abstract
The Western Isles have a very rich lime-burning history. The physical evidence for this lies within the many lime-bonded chapels, castles, burial aisles and houses which have been constructed here since the medieval period, most of which now litter the islands in ruins. The substantial erosion of external lime coatings from these structures, however, makes it difficult for today’s visitor to appreciate how striking they once were, let alone glimpse something of what the perception of them may have been within the medieval settlement landscape. Archaeological descriptions of mortar composition and interpretations of its use are also often much more cursory or inaccurate than they might otherwise be, and even occasionally fail to document evidence for a mortars existence at all. This is particularly problematic when surviving mortared masonry contexts may be important for dating a ruined structure, but the evidence is both fragmentary and complex. More widely, in the analysis of upstanding ruined buildings which often only display two materials – stone and mortar - ‘mortar archaeology’ should be an important and fully integrated part of any archaeological survey. A better understanding of how lime mortars might have been manufactured and applied within a given region, as well as how they may have degraded, will lead to a deeper archaeological understanding of how specific buildings developed. Ultimately, this knowledge will engender more explicit discussion of how mortar evidence is described and interpreted by archaeologists, and so enable a more informed post-survey debate and a better general understanding of how the wider built landscape has developed. This essay presents some preliminary results from one aspect of this research and outlines how some key mortar technologies in the Western Isles have developed over time. Interpreting this development, however, also requires a broader understanding of the political and cultural changes taking place when these mortars and buildings were being created. Lime-bonded buildings, like their dry-stone or turf predecessors and contemporaries, are not just practical responses to an environment in which people sought improved comfort and shelter – lime mortars are political and cultural players.

Journal
Journal of the Building Limes Forum: Volume 19