DECKING
THE HIDDEN RISK IN DECKING SPECIFICATION:
WHY SLIP RESISTANCE MUST BECOME A NON-NEGOTIABLE
Image courtesy of the Outdoor Deck Company Ltd
Across the UK, decking has become a defining feature of contemporary landscape architecture— integrating seamlessly into parks, waterfronts, education settings, hospitality venues and public realm schemes. It is often valued for its aesthetics, sustainability credentials and ability to create warm, inviting outdoor spaces. Yet behind the visual appeal lies a persistent and underacknowledged problem: the industry continues to accept decking systems whose real-world slip resistance has not been proven to be safe in the conditions in which they will actually be used.
Slips and falls remain one of the most common causes of major injury in public and workplace environments. Rainfall, shade, biological growth, moisture retention and high footfall all increase the likelihood of incidents, and these are precisely the conditions in which landscape decking is routinely installed. Despite this, many specifications still rely on generic“ anti-slip” claims, dry-condition test data, or ratings that have limited relevance to UK public-realm use. For a profession that emphasises evidence-based design, this gap between expectation and reality is increasingly difficult to justify.
What Safe Performance Should Mean The preferred method in the UK for assessing pedestrian slip resistance is the pendulum test, which provides a Pendulum Test Value( PTV). For surfaces exposed to wet conditions— common across almost all outdoor landscape applications— a wet PTV of 36 or above is typically understood to indicate low slip risk. In many situations, especially high-traffic or high-vulnerability environments, a more conservative threshold is appropriate.
However, too many specifications are underpinned by incomplete or inappropriate data. R-ratings generated from ramp tests continue to appear in marketing literature, yet these tests were designed for industrial environments with controlled footwear and do not reliably represent typical footwear or public use. Likewise, drycondition data is often emphasised even though the surface will be wet for much of the year. In some cases, suppliers simply offer no meaningful test information at all. Without verified wet-pendulum results from an accredited testing body, specifiers are effectively being asked to take safety on trust.
The Professional, Ethical and Legal Implications
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