Traditionally, the diagnosis of damage is largely based on the intuition and experience of the surveyor. However, this diagnosing process can be difficult to communicate, so that the underlying facts and assumptions often remain veiled, as this paper illustrates. Based on the results of a study of literature and a questionnaire, we suggest improving the diagnosing process. In this paper, we propose a systematic description of the development of damage, based on a uniform vocabulary and syntax. The syntax distinguishes between damage patterns, the processes leading to damage, and the factors that influence course and extent of these processes. Using this approach will help to share the knowledge that is currently embedded in intuition and experience, and enhance the retrievability of a diagnosis. Although the study is still in progress, the approach illustrates its benefits: the opportunity to learn from cases, and make this knowledge available to the profession.