Moisture control and problem analysis of heritage constructions

Buildings belonging to the cultural heritage are valuable assets and must be preserved for future generations. Therefore it is important that damaging temperature or humidity conditions caused by inappropriate construction measures are avoided. Even if the construction remains unaltered, changes in building operation may lead to moisture problems within the structure. In order to assess the effects of renovation or rehabilitation measures it is useful to study the moisture behaviour of all building components concerned. This can be done by monitoring the relevant conditions with sensors or by hygrothermal simulation with transient calculation tools. While monitoring will only provide the current status, hygrothermal simulations can also predict what will happen when the construction is altered or the indoor climate changed. Effective moisture control has to respond to the exterior as well as the interior moisture loads acting on building constructions. The paper explains the fundamentals, required input data and obtainable results of hygrothermal simulation models. It demonstrates how moisture problems may be investigated and eventually prevented by hygrothermal analysis. Finally, examples of European rehabilitation guidelines whose moisture control requirements were developed by hygrothermal analysis are given.