The design of a modelling, monitoring and validation method for a solid wall structure

Hygrothermal assessment is the combined analysis of heat, air and moisture transfer through the building fabric. The two approaches are covered by conventions known as the IS EN 5250: 2011 (Glaser method) and IS EN 15026: 2007 which differs from Glaser by solving the equations numerically using computer software. Results for hygrothermal analysis provide valuable information for surface and interstitial condensation risk assessment and the impact of energy upgrades. For traditional solid walled structures, conditions such as wind driven rain (WDR) and rising ground water can have a significant impact on the environmental behaviour and in particular the moisture behaviour of the building envelope. The convention IS EN 5250: 2011 is still widely used to assess the moisture performance of buildings and their components, even though it is not a comprehensive assessment methodology as it fails to include the movement of liquid water and for solid wall structures in particular, it is imperative that all forms of moisture movement are assessed. This research sets out a design methodology, to establish the hygrothermal performance of rendered solid brick wall constructions to ultimately establish the optimum and most appropriate retrofit intervention. The methodology chosen establishes all material properties of a monitored wall. A weather station is used to establish all weather data for the site. The building, will be monitored initially for a 12 month period to determine its hygrothermal condition. The data logged monitoring will establish the temperature and RH profile through the wall. The data from this monitoring will be inputted to software which meets the IS EN15026: 2007 convention-a dynamic model which assesses the movement of water both as a vapour and as a liquid.