Moisture risks arising from retrofitting: The safest technical solution is not always the best solution

In the coming years insulation in buildings will need to be retrofitted to save energy. The article focuses on the difficulty in choosing the best way of retrofitting the insulation as e.g. safety, aesthetics and costs are often prioritised differently in each project, depending on the context for the building and the building owner. As an example, the paper describes risks arising from retrofitting with emphasis on moisture safety, as high moisture levels may lead to health problems for the building users. The example illustrates the difficulty in obtaining moisture safety and energy savings at the same time when retrofitting by internal insulation. However, moisture-related health risks are mainly personal, as they depend i.a. on age, gender and medical history. This raises the question of whether the building owner should be allowed to choose whatever he wants, with the risk of extreme prioritisations, or whether society should ban some solutions, because they may be too risky for some building users. On the other hand, can society afford to make all retrofitting safe also for the weakest? Based on a review of literature, the paper outlines how these dilemmas are described and handled in Denmark today. The aim is to operate with a combination of information on why some solutions pose more risks than others and descriptions on how the risks are reduced. The best solution is found by weighting potential energy savings, costs, aesthetics and health risks. Consequently, the best solution is not necessarily the safest technical solution; it depends on an evaluation by the building owner or user. However, the risk is not quantified. To make the decision more objective in the future, a more quantified prioritisation might be possible by defining moisture safety classes for buildings, describing which buildings should only be used by people who are not prone to
moisture-related health problems and which can be used by more sensitive users.