Thermo-hygric properties of a newly developed aerogel based insulation rendering for both exterior and interior applications

A new kind of rendering based on silica aerogel granulates was developed showing a high performance namely a low thermal conductivity and a low vapour transmission resistance, a combination of characteristics unachieved by existing renderings. This insulation rendering has a clear advantage over insulation boards which need a plane subsurface, adjustment, gluing and even fastening by means of dowels. A thermal conductivity of around 25 mW/(m K) and a water vapour transmission resistance of 4 has been achieved. Its applicability to walls both manually and by a plastering machine was proven and measures were taken to keep the thermal conductivity low for both methods. Its first market will be in retrofitting of old and historically sensitive buildings.