As levels of thermal insulation and air tightness in buildings are improved, moisture management has become an increased concern. Approved Document Part C2, resistance to moisture, provides you with limited clarity as it references withdrawn guidance and calculation methodologies. So we use our extensive understanding of moisture and heat movement within buildings to provide you with design advice, as well as detailed calculations that follow the guidance set out in the code of practice for control of condensation in buildings (BS 5250:2011+A1:2016).

Depending on the complexity of the plane element being assessed, we use our principle-based understanding to provide different levels of interstitial and surface condensation risk assessments. We can help provide you with prescriptive guidance for simple elements, simplified modelling following BS EN ISO 13788:2012 (which is commonly requested by Building Control for lightweight, airtight structures), or more complex numerical simulation in line with BS EN 15026:2007 (for build-ups in environments which increase moisture transport and storage). For junctions within a building envelope we use 3D models to assess the transfer of heat, identifying potential areas of low temperature and high humidity and applying the methodology in BRE IP17/01 and BS EN 13788:2012 to check the risk of surface condensation and mould growth. We also rely on modelled temperatures through the building element to check interstitial condensation risk for junctions.