The Influence of Aspect on the Biological Colonization of Stone in Northern Ireland.

Catherine Adamson, Stephen McCabe, Patricia Warke, Daniel McAllister, Bernard Smith

Research output: Contribution to journalArticle

16 Citations (Scopus)
23 Downloads (Pure)


The rate and type of biological colonization of stone is influenced by a wide array of environmental factors in addition to substrate characteristics. A series of experiments was designed to compare the rate and type of biological colonization of stone at varying locations over a 21-month time period. Exposure
trials were set up at nine different sites across Northern Ireland that covered a wide variety of environmental conditions. To determine aspect-related differences in colonization, blocks of Peakmoor sandstone and Portland limestone were placed on the north- and south-facing sides of purpose-designed exposure racks. Colorimetry and visual analysis were carried out on collected samples at increasing time intervals. Results showed significantly different rates of darkening and greening over time between north-facing and south-facing blocks, for both sandstone and limestone. This difference is likely to be representative of the fact that in Northern Ireland’s wet climate and northern-latitude position, the north face of a building will receive less direct sunlight. Therefore north-facing blocks, once wet, will remain damp for much longer than blocks on other façades. This slow-drying phenomenon is much more hospitable for biological colonization and continued growth than the hostile environment of rapid wetting and drying cycles experienced on the south face.
Original languageEnglish
Number of pages10
JournalInternational Biodeterioration & Biodegradation
Publication statusPublished - Aug 2012


  • Aspect Colonization Greening Sandstone Algae

ASJC Scopus subject areas

  • Biomaterials
  • Microbiology
  • Waste Management and Disposal

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