The pressures generated by aircraft trailing wake vortices can greatly exceed the normal design load for roofs. Damage is generally confined to small-format roofing elements, such as tiles and slates, on buildings near the ends of runways in urban areas. This Digest, which replaces Digest 391, helps building owners, occupiers, roofing specifiers, contractors, installers, and local andairport authorities, to identify and avoid damage to tiled and slated roofs from aircraft trailing vortices by suggesting minimum safe fixing standards. 12 pages.