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. (C) 2011 Elsevier B.V. All rights reserved.