Please note that this is a scanned copy of a paper originally published in 1996, so the text is not as clear as in documents created as pdf files.

This Digest provides guidance on the prevention of damage to external surfaces by birds, ’masonry bees’, climbing plants and creepers, and biological growths. It describes how these animals and plants can cause deterioration in surfaces and mortar joints, and suggests both preventative measures, and methods of treating affected surfaces.