Ivy on Walls Research Project


The principal aim of the project is to systematically investigate whether Common ivy (Hedera helix) as well as other types such as Canary Island ivy (Hedera canariensis), that are mostly found on boundary walls in the present day, are acting biodeterioratively or bioprotectively with the stone material comprising these walls. The spatial extend of the study is in England, including sites in Oxford (Rewley Abbey, the Old City Wall, and at Trinity, Pembroke, and Worcester Colleges) and elsewhere in the Southeast (Dover), the Southwest (Nailsea, near Bristol), in the Midlands (Leicester), and in the North (at Byland).

There are several key research questions to be addressed, as follows:

  1. To what extent does ivy affect changes to micro- and macro-climate at the stone surface and are these changes favourable?
  2. What are the physical and chemical effects of ivy rootlets?
  3. Under what circumstances does ivy root into walls?
  4. Do ivy roots in the ground pose a problem?
  5. What is the best management strategy with regards to ivy on walls?

To examine each of the research questions, field monitoring and experiments as well as laboratory experiments will be conducted at various scales. Field investigations shall comprise of:

  • detailed mapping at each of the sites,
  • construction of a test wall at a site near Oxford,
  • possibly high-resolution ground penetrating radar (GPR),
  • 2D resistivity surveying of Oxford sites to measure moisture content, and
  • use of dataloggers (and iButtons for the Oxford sites) to assess temperature and relative humidity of microclimate beneath the ivy canopy and on uncovered areas.

Research project dates: 2006-2010 (Phase 1) and 2012-2016 (Phase 2)

Primary researchers involved:

Academic Lead: Prof Heather Viles

Affiliations (and funding source): Historic England, Alan Cathersides

Researchers: Dr Martin Coombes (2011-2016); Dr Troy Sternberg (2007-2010); Hong Zhang


Link to the Phase 2 report outputs


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