Many freestanding walls have been in service for decades or even centuries. But if these walls are not well-built to start with, they can fail early in their life, and soundly-built walls can be damaged or even collapse completely if local conditions change. Before starting on any repair, whether a minor patching up or a major rebuilding, it is important to find out what caused the problem. Failure to do that can easily lead to a recurrence. This Guide aims to help in assessing the damage in freestanding masonry walls, establishing the cause, and carrying out an effective repair. It does not cover parapets or walls built as retaining walls. 6 pages.