Stability Relevant Properties of an SiO2 Aerogel-Based Rendering and Its Application on Buildings

Aerogel-based renderings and plasters have been spreading throughout Europe for nearly a decade. Several national and EU-funded projects have addressed this interesting building product, both at research level within academia and at application level within R&D of renowned industrial enterprises. At present, a number of investigations into the hygro-thermal, chemical and application properties of a commercially successful aerogel-based rendering and its main ingredient, SiO2 aerogel granules, have been undertaken. Immersion in water showed that even under harsh circumstances water does not enter the aerogel granules, but rather accumulates in the porous phase surrounding the granules. A further immersion in calcium hydroxide at different temperatures did not affect the aerogel granule either, which indicates the robustness of the granules with respect to their exposure to moisture and chemical deterioration emerging from the construction materials the rendering is applied on. An executed application to a historic building with a structured finish, and without any reinforcement mesh, showed the advantage of a versatile applicability of this rendering when the external appearance and visible details of a facade must be kept unchanged. The investigation is rounded off by an infrared picture taken on a cold day showing the thermal influence of the aerogel-based rendering, and its effectiveness for reducing heat loss in buildings.