Full Description

Cross Laminated Timber (CLT) is increasingly used as structural component in low and mid-rise buildings. It comes with excellent carbon storage and prefabrication potential, and provides an interesting alternative for traditional construction methods. However, as it consists of wooden components, these panels are prone to degradation and delamination if exposed to long-term moisture sources, typically originating from on-site exposure to rain spells during the construction period. This study investigates different drying strategies by analyzing the wetting and drying processes by means of HAM-simulations for a CLT floor in a case-study with moisture-related degradation problems. Bore samples were taken from the CLT balcony where the most severe deterioration was observed, caused by insufficient rain protection during construction. After a rainy winter period the CLT was prematurely sealed off with an unventilated ETICS system (EPS + silicone plaster). In the analyses, it is seen that an unventilated finishing system results in a critical deterioration of the timber. The simulations show this could have been prevented by either choosing a ventilated finishing system or by sufficient rain protection during construction. In order to compare simulations with measurements, it is important to adopt a clear methodological approach for the hygrothermal simulations. Hence, a framework was developed that elaborates on each step of the development process of HAM-simulations, by means of a strategic three level selection system for model parameters. This approach allows to increase the usability and reliability of HAM-simulation in practice. At the end of the stepwise framework, the hygrothermal response from simulations was compared with the visual and experimental assessment of the wood samples. The study highlights the potential of HAM-simulations in both design as litigation context, and it was concluded that practice would benefit from a stepwise framework to conduct HAM-simulations, that provides guidelines to select climate, materials and performance criteria.

Product Details

Published: 2022 Number of Pages: 9 Units of Measure: Dual Product Code(s): DBldgsXV-C036