Green or slippery composite decking: algae, dirt and safe cleaning

Where green growth develops #

Shaded, slow-drying areas beneath trees or beside planters often retain damp organic debris. Growth may be on surface deposits and is not, by itself, proof that the board core is rotting. Conversely, softness, cracking or movement must not be dismissed as ordinary algae. Check both surface condition and construction.

Cleaning without creating another hazard #

Keep people off the affected route while cleaning and drying. Remove leaves and loose dirt, then use the permitted method for that surface. If a specialist algae product is needed, obtain compatibility confirmation and follow its label. Keep runoff away from ponds and planting as directed; never mix chemicals.

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Reduce the conditions that support recurrence #

Maintain accessible gaps and outlets, move planters onto suitable feet and review persistent shade where practical. Clear obstructions without widening gaps or cutting boards casually. Repeated pooling after rain is a reason to ask the installer about slope, support and ventilation, not simply to buy stronger cleaner.

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Slip resistance is a system issue #

Footwear, surface contamination, weather and cleaning practice affect real walking conditions. A laboratory slip result relates to stated conditions, not an assurance that no one can fall. On public routes, arrange suitable risk assessment and maintenance responsibilities. Reopen the area only when its condition is safe for use.

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Product instructions come first #

Identify the manufacturer, collection, capped or uncapped surface and installation date before choosing a treatment. A method suitable for one composite can damage another. Start with loose-dirt removal, then a small test using the permitted cleaner and a soft non-metal brush. Rinse thoroughly and assess when completely dry. Follow the product's dilution, contact time and care instructions; never mix cleaning chemicals. Restrict access while the surface is wet or unsafe.

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Green Plank product support #

For Green Plank decking, fencing or cladding, request the current care instructions for your exact profile and finish. The Green Plank links below are commercial documentation resources. These guides provide general care advice, not a product certification or a decision on any individual warranty claim.

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Practical inspection checklist

Common questions