Abstract
Increasing climate fluctuations and extremes due to climate change are particularly concerning for wooden building envelopes, especially in the Nordic region, which has harsh climatic conditions. The exterior coating’s barrier properties are crucial for maintaining building envelopes’ intended lifespans. Hence, it is unfortunate that the vapor resistance of exterior coatings is not openly accessed for commercial products. This study investigates the influence of the water vapour resistance of exterior coatings on the moisture conditions and mould growth risk of ventilated wooden claddings. The sd-value (vapour diffusion-equivalent air layer thickness) is determined for nine free-standing coatings (alkyds, emulsions, and acrylics); in total, 100 specimens are tested with the wet cup method. Additionally, with WUFI Pro, one-dimensional hygrothermal simulations under Nordic climatic conditions investigate how the coatings’ vapour resistance might influence the moisture dynamics of wood. The mould risk is assessed by the add-on WUFI VTT Model. The determined sd-values for the coatings range from 0.453 to 1.350 m (three layers) and from 0.690 to 2.250 m (six layers), showing a strong correlation with the dry film thickness. The vapour resistance of the coatings does not significantly influence the wood moisture content, but lower resistance may cause slightly faster drying. The importance of surface treatment is confirmed. The mould risk is notably higher in a Stavanger climate on a southwest-facing wall compared to Trondheim on a north-facing wall.
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
