Interior super insulation in heritage buildings: Challenges and possibilities to conserve heritage values and increase energy performance

Report, 2020

Super insulation materials (SIM) are insulation material with a very low thermal conductivity, even lower than stagnant air. The aim of the project has been to show how these materials can be used to save energy and space, as well as to contribute to preservation of exterior character defining elements while maintaining the temperature and humidity performance of the walls when renovating buildings built before 1945. The project was performed by researchers in the fields of building physics and building conservation. Brick buildings in Sweden have been in focus, as these buildings have one of the largest energy efficiency potentials in the entire building stock. Brick buildings often challenge engineers and architects by having contradicting demands on energy efficiency and cultural heritage values. Often, the façades of these buildings have valuable character defining elements that make them difficult to insulate. There are also problems with the building components, technical service life and insufficient thermal comfort indoors. Experts in architecture and building conservation have contributed with knowledge through interviews and practical work at study visits and by reviewing drawings and construction documents. Collaboration partners, linked to the reference group, contributed to the project with their knowledge in interviews, meetings and seminars. The project has led to an increased knowledge and understanding of the technical difficulties that exist when preserving character defining elements while imposing energy efficiency measures with super insulation materials in buildings. Advantages of super insulation materials are, for example, that they add little thickness to the walls and that the flexible materials, such as aerogel blankets, can contribute to preservation of character defining elements in heritage buildings. The disadvantage of using super insulation materials as interior insulation is, as for all insulation materials, that the lowered temperatures in the wall can lead to increased moisture levels and also that the drying out capacity of the wall can decrease. Due to the risks with interior insulation of walls, it is important to thoroughly investigate if the wall is suitable for interior insulation.