Drying Potential of Wood Frame Walls Subjected to Accidental Water Infiltration

Abstract

Wood frame construction is the most widespread building method. In Belgium the number of wood frame buildings has grown in the last years: in 2018 over 10% of all new built dwellings were wood frame buildings. This increase can be partly attributed to the growing attention for energy performant buildings with a low environmental impact. In contrary to masonry construction, wood frame is more vulnerable to moisture problems, mould growth and wood rot. An important risk is water infiltration through imperfections in the building envelope as a result of driving rain. Therefore it is important for the design to be resilient and allow drying without consequential damage. To analyze the drying potential, an experimental set-up with 8 wood frame compartments was built. The compartments differ in the type of insulation material (mineral wool or cellulose) and the type of vapour retarder (OSB or smart vapour retarder) that were used. In this way 4 types of compartments were obtained, each having a different combination of insulation and vapour retarder. Of each combination there are 2 identical compartments. This allows to insert water in one of both, to mimic rain water infiltration from the outside into the compartment. Temperature, relative humidity and moisture content were measured on different locations in the construction (in total 92 sensors). In this way, the hygrothermal performance of the compartments with and without water infiltration can be analyzed, as well as the drying rate.