The Future Climate Moisture Susceptibility of Wall Assemblies: Analysis Based on Monte Carlo Simulation Using a Simplified Deterministic Hygrothermal Simulation Model

Abstract

A newly developed generic algorithm to assess moisture susceptibility of simplified wall assemblies has been developed within the CIB-W080 WG 2. This group is focusing on guidelines for design for durability of building envelopes. The algorithm is implemented in a publicly available Matlab code. A simplified wall assembly consisting of up to four material elements is considered. Optional vapor retarder and thermal resistances are located between the elements. In this paper modelling of a ventilated cladding is implemented. Using the simplified numerical model, a probability‐based risk analysis using the Monte Carlo method is demonstrated. The risk assessment of the wall assembly considers the interior and exterior climatic load. The moisture transport mechanism accounted for in the analysis is diffusion. The rain load is assumed to be transferred directly to a chosen outer susceptible material element in the construction. An insulated wooden wall structure is analyzed and the probability distribution of the time of wetness is presented for cases using sequence of 31 consecutive climatic years, randomly varying indoor moisture excess, indoor temperature and driving rain leakages.

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