Landscape and urban design professionals increasingly operate under heightened expectations regarding safety, inclusivity and accountability. When a decking surface becomes slippery after the first winter, users do not distinguish between product, contractor and designer; they simply recognise a failure of the environment to meet their needs. For clients in education, leisure, local government and healthcare— where vulnerable users are common— such failures can have significant implications.
From a legal and compliance perspective, designers and asset owners are expected to demonstrate that they have reduced foreseeable risks“ as low as reasonably practicable.” If a surface is known to be at risk of becoming slippery when wet, and more robust alternatives exist, it becomes difficult to defend the specification of a system without verifiable performance evidence. In short, the absence of reliable test data becomes a liability.
Climatic and Demographic Pressures Climate patterns are shifting, bringing more prolonged damp conditions, more intense rainfall and greater variability in seasonal contaminants such as algae, leaf litter and pollution films. These changes make real-world slip performance more critical than ever. At the same time, public spaces are being designed for increasingly diverse and ageing user groups. Older people, children and individuals with mobility impairments are more susceptible to slips and more likely to suffer serious consequences. A decking surface that becomes hazardous in predictable conditions is incompatible with modern expectations of accessibility and inclusive design.
Performance-Led Specification: A More Rigorous Approach To achieve robust and predictable safety outcomes, landscape professionals may wish to adopt a more structured approach to decking specification:
DECKING
1. Set a clear minimum performance requirement. For wet-exposed environments, a wet PTV of at least 36 should be considered the baseline, with higher targets applied in areas of heavy use, contamination or increased vulnerability.
2. Require independent, up-to-date test reports. These should be conducted in accordance with current recognised standards, clearly stating test conditions, direction of travel and the sliders used.
3. Consider contamination profiles. Decks beneath trees, adjacent to water, shaded by structures or subject to organic debris will not behave like clean, evenly exposed test samples. Systems should be evaluated for their ability to maintain performance in realistic conditions, not just ideal ones.
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