Facade degradation risks in relation to energy renovation: towards a clear decision framework.

Extensive research has been made on the hygrothermal behaviour of building envelopes over the past two decades. Heat Air Moisture (HAM) models are found valuable tools to assess the risk on deterioration and premature failure of building components due to freeze-thaw action, mould growth, wood decay... Although HAM tools like WUFI and Delphin are commercially available, their practical application remains limited. However results of these tools might provide relevant insights in the feasibility of energy renovation projects. An important reason is the unreliability on the results due to uncertainties on input parameters, e.g. the difficulty to measure material properties or to define deficiencies as air leakage and water infiltration. Next to that, degradation models often require additional post-processing, making it less accessible to practitioners. This proposal aims to develop a methodology to convey the results and insights from extensive hygrothermal simulations to the building industry. The methodology will allow the integration of rules of thumb, decision trees and stochastic risk assessment in an overall decision framework. Not only do’s-and-don’ts but also guidelines on individual cases are included, e.g. which measures will reduce uncertainties on damage risks. The decision framework will improve decision-making for building practitioners, and allow a more quantitative approach towards risk management and balancing the costs against the potential degradation risks.