Commissioning of moisture safety of nZEB renovation with prefabricated timber frame insulation wall elements

An improvement in energy performance for existing buildings is needed to fulfil EU energy policy. The efficient way to accomplish the idea of nearly-zero energy buildings (nZEB) is to apply the integrated design process and application of prefabricated insulation elements paired with the expertise of hygrothermal performance. In the current study, the commission of design and construction with emphasis on moisture safety, relying on known quality control programmes, was applied to assure the compliance of nZEB renovation results of an apartment building, where prefabricated timber frame insulation elements were used. The results confirming that the mould index is below critical level M < 1 and moisture content, drying out from the concrete envelope within first 6 months post installation of elements, was 23 kg/m3 and after that, during the next 12 months 12 kg/m3. Analysis showed that it is necessary to force contractors and developers to put into practice quality assurance and moisture safety commissioning processes as a mandatory part of contracting. The results have shown that thorough inspection, strict rules of moisture safety and analysis of designed solutions before, during and after renovation are essential and worthwhile for high-quality, sustainable outcomes of nZEB renovation with timber frame insulation elements.