The durability of brick and structural clay products used to be expressed purely in terms of frost resistance, but it now covers a broad range of functional and damage mechanisms. This subject has been of concern for producers and users alike for many hundreds of years. In earlier times, the cause of damage was mainly clarified on the basis of empirical data. That was supposed to be enough to guarantee good, durable bricks and tiles. Nowadays, though, the quality of modern heavy clay products is assured by a wide array of technical rules, a comprehensive quality management system and a manifold repertoire of test and analysis methods. Then as now, however, the quality of bricks and tiles, as tradition-steeped clay-based products, depends on people and their skills.

By way of specific practical examples of historical and modern brick architecture, different types of damage and their causes are presented, discussed and illuminated with the help of various analytical techniques.

Appropriate to the theme, progress made to date in the generation of a new WTA specification governing the preservation and repair of historical clay masonry (German title: Erhaltung und Instandsetzung von historischem Ziegel- und Klinker-Mauerwerk).

Dipl.-Ing. Alexander Freyburg, MFPA Weimar