ABSTRACT
The high energy consumption of existing buildings is mainly caused by the poor thermal insulation of the building envelope which can be improved by the addition of an additional layer of insulating material such as polymer foams. However, in many cases it is impossible to add this layer of 20 cm or more onto an existing façade, especially not for buildings which are part of the cultural heritage. Since many of these historically valuable buildings have mineral renderings, a rendering system with a very low thermal conductivity of approximately 0.025 W/m*K was developed. This high performance rendering is based on aerogels, a highly porous material (porosity of 80%–99.8%) which is produced by a sol-gel process. Thanks to an optimized combination between the type of aerogel and the binder material it was possible to produce such a rendering system which still can be applied by standard techniques. Presently, the first large scale projects with this material are realized in the field.
