Aerogel-based plasters for renovation of buildings in Sweden: Identification of possibilities, information deficiencies and challenges

Licentiate thesis, 2021

Aerogel-based plasters are a class of high energy efficient wall finishes with declared thermal conductivities around 30-50 mW/(m∙K). Aerogel-based plasters are promising alternatives to substitute conventional insulation materials when renovating uninsulated building envelopes. Aerogel-based plasters have been successfully used in several buildings in a number of European countries but seldom in regions with cold, wet, windy climates combined with freeze-thawing. The potentials for introduction of aerogel-based plasters in Swedish buildings are large as around 27 % of all multi-family residential buildings in Sweden have façades covered by plasters. By using aerogel-based plasters in the renovation of listed buildings, new possible alternatives for solving some of the existing challenges in the renovations of such buildings can be created.

This thesis summarizes the work done on addressing the possibilities and challenges associated with the application of aerogel-based plasters in Sweden. The study is from a risk assessment point of view with focus on the hygrothermal performance, long-term durability and compatibility of aerogel-based plasters with other materials when installed in multilayer wall configurations. Literature review, semi-structured interviews, numerical energy simulations, study visits and laboratory measurements are the selected methods for the purpose of this study.

The results of the study show that APs are promising materials to improve the energy efficiency in buildings when renovating existing buildings in Sweden. However, and despite the large research efforts on aerogel-based plasters, a complete and reliable set of hygrothermal and mechanical properties for aerogel-based plasters is still lacking. Information about these properties is necessary to perform advanced hygrothermal- and risk assessment analyses. To confirm the performance and to justify the higher investment cost of aerogel-based plasters, their long-term durability and compatibility with other building materials need to be further explored as well. For the future introduction of aerogel-based plasters in Sweden, reliable information and documentation are needed. These are needed to evaluate the economic aspects, service life and adaptability of the material to the Swedish building regulations.