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Hygrothermal Degradation in Tiled Surfaces

Understanding Hygrothermal Degradation Issues with External Tiled Balcony Areas

The term "Hygrothermal Degradation" effectively conveys the dual impact of moisture and temperature on external tiled balcony areas, highlighting the need for a holistic approach to address these issues. It's important to recognise the interconnected nature of these factors for effective diagnosis and remediation.

External tiled balcony areas, particularly in regions with variable weather conditions like Perth, are susceptible to a range of issues when leaks in the tiled surface finish allow water to penetrate to the screed substrate. This scenario is not uncommon on older properties, and we also see the issues on new properties where there are tiling faults and defects. The issues can result in a cascade of problems, which need careful attention. Here is a breakdown of the process and its associated challenges:

1. Water Penetration and Retention: When water infiltrates through the top surface of the balcony tiles, it can be trapped within the structure. This retained water accumulates over time, with each rainfall contributing to the problem.

2. Damage to Waterproof Membranes: Most under-tile waterproof membranes are not designed to be permanently submerged in water. In cases where the substrate and / or screed is water-logged, this can impact the serviceability and warranties of these materials. 3. Heat-Related Vapourisation: During the summer months, Perth experiences high temperatures. As the external tiles heat up, the retained water trapped under them can reach a point where it turns into vapour. This transformation from liquid to gas causes several critical issues:

3. Damage to Grout: The vapourisation of trapped water can exert pressure on the grout lines, causing them to weaken or crack. This not only compromises the structural integrity of the tiling but also affects the aesthetics of the balcony.

4. Water Expulsion through Grout: As the vapourisation process continues, it can force water out through the weakened grout lines. This escaping water can lead to further damage and potential structural issues within the balcony area.

5. Tile Deterioration: The process of water vapourisation and the subsequent expulsion can also result in 'drummy' tiles. These tiles sound hollow when tapped, indicating detachment from the substrate. This compromises the stability and safety of the balcony surface.

Addressing these issues involves a comprehensive assessment of the balcony's waterproofing system and tile installation. It's crucial to identify and rectify any areas where water infiltration occurs, in addition to repairing or replacing damaged tiles and grout.

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