The use of Exterior Thermal Insulation Composite Systems (ETICS) has increased in recent decades, primarily due to its straightforward installation methodology, which is beneficial for cost-efficient energy renovation of buildings. ETICS, being a non-ventilated facade system, has encountered challenges in weather protection of insulation and the growth of bio-organisms on plaster surfaces, compared to ventilated systems. The carbon footprint of the building is, in addition to the energy use during use, also greatly influenced by the materials used. Here, bio-based materials are at the forefront with a smaller footprint. In the current study we present preliminary results from field measurements of the hygrothermal performance of CLT external walls with a wood-fibre-based ETICS with rain penetration scenarios.
A prefabricated modular test house was constructed from CLT to investigate the hygrothermal performance of CLT covered with ETICS. The north-facing external wall was segmented into five sections to investigate the effect of the weather protection membrane and rainwater penetration. Field measurements included monitoring temperature [t, °C] and relative humidity [RH, %] between the CLT and the insulation or membrane, between the insulation and the membrane, and between the insulation and the rendering system.
The preliminary findings from field measurements suggest that further investigation is needed for the examined external wall solution before definitive conclusions can be drawn. The area most critical to mould growth was identified to be between the rendering system and the insulation. Therefore, it is important to conduct further investigations into the mould sensitivity of both the insulation and the rendering system. A calculation model based on preliminary measurement results has been created. However, accurate determination of material properties and an extended measurement period with prolonged leakage periods are essential for more precise validation. In addition to determining material properties, the impact of wetting wood-fibre insulation on adhesion with the rendering system and the mechanical properties of the insulation in general is important for conducting a lifecycle analysis on ETICS with bio-based insulation.
Keywords: cross-LaminatedtTimber, wood-fibre insulation, ETICS, Ggreen construction
Authors
Villu Kukk
Tallinn University of Technology, Estonia
Targo Kalamees
Tallinn University of Technology, Estonia
Jaan Kers
Tallinn University of Technology, Estonia
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