Non slip decking refers to timber or composite deck surfaces engineered or treated to maintain surface friction under wet, icy or debris covered conditions. Understanding how to make your decking non slip is essential, as slips and trips remain one of the leading causes of non fatal injuries. The UK Health and Safety Executive reports that they account for over 30% of workplace injury cases annually. The Royal Society for the Prevention of Accidents also identifies wet outdoor surfaces as a major seasonal hazard during autumn and winter.

This article examines why decking becomes slippery, the mechanical and chemical methods used to increase traction, material design considerations, performance standards, and the long term limitations of anti slip systems.

Why Decking Becomes Slippery

Decking becomes slippery because moisture reduces friction between footwear and surface fibres. Timber absorbs water, while composite boards retain surface moisture, both lowering traction under load.

Moisture and Surface Friction

Surface friction depends on texture and water displacement. When rainwater forms a thin film across decking boards, it reduces direct contact between shoe sole and surface. Research published in the Journal of Safety Research shows that wet contamination significantly lowers the coefficient of friction compared to dry conditions.

Algae and Organic Contamination

Algae growth further decreases traction by creating a biofilm. Shaded areas accelerate growth due to prolonged dampness. The Health and Safety Executive notes that biological contamination contributes directly to outdoor slip hazards.

Surface Wear and Ageing

Foot traffic gradually smooths timber grain, reducing mechanical grip. While composite decking resists splintering, smoother finishes can also lose traction over time.

Methods to Make Decking Safe and Less Slippery

If you are assessing how to make your decking safe and less slippery, the solution involves either increasing surface friction or reducing moisture retention.

1. Regular Mechanical Cleaning

Cleaning removes debris that traps moisture and promotes algae formation. Sweeping every one to two weeks limits organic build up. Annual deep cleaning restores surface texture without damaging fibres.

2. Application of Anti Slip Coatings

Anti slip oils and coatings increase friction by embedding aggregate particles within the finish layer. These particles create micro texture that improves grip in wet conditions.

However, coatings require reapplication. Over time, surface grit can wear away under heavy foot traffic.

3. Non Slip Decking Strips

Mechanical strips provide consistent traction by introducing an abrasive insert fixed directly to the board. Unlike coatings, strips do not rely solely on surface adhesion.

• Installed across the direction of travel

• Suitable for steps and high traffic zones

• Minimal performance reduction in wet conditions

While effective, strips alter visual appearance and may not suit all design preferences.

4. Drainage Optimisation

Improving drainage reduces standing water, which directly lowers slip risk. Decks should incorporate slight fall gradients to allow runoff. Blocked board gaps prevent drainage and increase moisture retention.

Material Choices and Built In Traction

Material selection determines baseline slip performance before treatments are applied.

Grooved Timber Boards

Grooves increase drainage channels and directional grip. However, grooves can also trap debris, requiring more frequent cleaning.

Textured Composite Decking

Manufacturers produce composite boards with embossed grain patterns to enhance traction. These surfaces resist rot but still require cleaning to prevent biofilm formation.

Factory Integrated Anti Slip Inserts

Some decking boards incorporate abrasive strips during manufacturing. These provide durable traction without surface reapplication cycles.

Slip Resistance Standards and Measurement

Slip resistance is measurable using Pendulum Test Values, which assess friction under wet conditions. According to the UK Slip Resistance Group guidelines, a PTV score above 36 indicates low slip potential in wet environments.

Specifying products tested to recognised standards ensures measurable safety performance rather than relying on marketing claims.

Limitations and Edge Cases

When Anti Slip Fails

Even treated decking becomes slippery if algae accumulates. Anti slip coatings do not eliminate maintenance requirements.

Salt and Ice Melt Damage

Rock salt accelerates timber fibre breakdown and can corrode metal fixings. While salt improves ice melt speed, it compromises long term structural integrity.

Excessive Texture Risks

Highly abrasive surfaces improve traction but may cause barefoot discomfort or accelerated wear on footwear.

Timber vs Composite in Extreme Conditions

Timber absorbs moisture but dries faster in ventilated environments. Composite resists rot yet may retain surface water longer in shaded areas.

Long Term Strategy for Safer Decking

Ultimately, understanding how to make your decking safe and less slippery requires a combined approach. Long term slip reduction integrates structural drainage, regular maintenance, and mechanical traction systems. For high risk environments such as commercial walkways, specifying decking tested to recognised slip resistance standards provides measurable assurance beyond visual inspection alone.

No single treatment permanently eliminates risk. Sustainable safety depends on material selection, correct installation, and ongoing maintenance.