Decking Cleaner | Algae & Wood Decking Cleaner

Restore, Revive and Protect Your Wooden Decking

Decking takes more punishment than almost any other outdoor surface. Exposed to rain, frost, UV, leaf fall, and the constant threat of algae and green mould, even well-built timber decking can look tired, discoloured, and dangerously slippery within a single season if it isn't properly maintained.

The right decking cleaner doesn't just lift surface dirt, it removes biological growth, opens up the timber grain, and prepares the wood for long-term protection.

At GK Products UK, our decking cleaner range covers every stage of wooden decking care: from removing algae and mould, to treating oil stains, to restoring weathered timber to a finish that looks close to new. Whether you're doing an annual spring clean or tackling decking that's been neglected for years, you'll find the right product here.

Why Algae on Decking Is More Than an Aesthetic Problem

Algae on decking is one of the most common, and most hazardous, maintenance problems in UK gardens. Decking sits close to ground level, often in partially shaded areas that stay damp after rain, which creates ideal conditions for algae, green mould, and mildew to take hold.

The result isn't just unsightly: a layer of algae makes wooden decking extremely slippery underfoot, creating a genuine safety risk for children, elderly visitors, and anyone using the deck in wet conditions.

Removing algae from decking requires more than a brush-down. Algae spores embed into the surface of the timber and will regrow quickly unless treated with a dedicated decking algae remover that kills the growth at its source. Our GK Decking Cleaner is formulated to do exactly that, breaking down and lifting algae, green mould, and biological staining from both softwood and hardwood decking surfaces.

A Complete Range of Decking Cleaners for Every Problem

Unlike many suppliers who stock a single product and call it a decking cleaner range, we offer a suite of products to address the full range of decking maintenance needs:

GK Decking Cleaner 5Ltr: our dedicated wood decking cleaner for removing algae, green mould, and general biological growth from timber decking surfaces. The go-to starting point for seasonal cleaning and algae removal for decking.
GK Concentrated Fungicidal Wash: a concentrated treatment for fungal growth, mould, and mildew. Ideal as a follow-up treatment or for decking with persistent fungal issues that keep returning after standard cleaning.
GK Wood Restorer 5Ltr: our decking cleaner and reviver for weathered, greyed, or discoloured timber. Restores the natural colour and character of the wood, making it an excellent preparation step before applying any oil, stain, or sealant.
GK Oil Out Oil Stain Remover 5Ltr: specifically for oil staining on decking caused by barbecue drips, teak oil over-application, or general spillage. Lifts oil penetration from timber without the bleaching effect of harsher treatments.
GK Multi-Surface Cleaner & Sanitiser: a versatile cleaner for composite and plastic decking as well as general garden furniture and outdoor surfaces surrounding the deck area.

The Best Decking Cleaner for Timber: What to Look For

With a wide range of decking cleaners available on the UK market, it's worth knowing what separates an effective product from one that simply shifts loose surface dirt. The best decking cleaner for outdoor timber will be specifically formulated to work with wood, not just on it.

That means chemistry that penetrates the grain to kill biological growth, rather than bleaching the surface and leaving the underlying spores intact. It also means a formula that cleans without stripping natural oils from the wood or leaving a residue that prevents subsequent treatment from bonding.

Our wooden decking cleaner range meets all of these criteria, and every product is suitable for use ahead of oiling, staining, or sealing, making them the natural first step in any full decking restoration project.

Recommended Cleaning Frequency

For most UK properties, cleaning decking at least once a year, ideally in early spring before the outdoor season begins, is the minimum needed to keep surfaces safe and presentable.

Decking in heavily shaded gardens, or in areas with significant tree cover and leaf fall, will benefit from treatment twice a year: once in spring and again in autumn after leaf fall.

Regular cleaning not only keeps the surface looking its best but significantly extends the life of the timber by preventing biological growth from establishing deep within the wood.

Questions about which product is right for your decking type, or how to approach a full restoration? Call us on 07557 111 297 or email sales@gkproductsuk.com, we're happy to advise. Free shipping on orders over £60 to mainland England, Wales and parts of Scotland.

Frequently Asked Questions

What is the best decking cleaner for algae removal?

For algae on decking, our GK Decking Cleaner 5Ltr is the recommended starting point. It's specifically formulated as a decking algae remover for timber surfaces, killing growth and lifting staining without damaging the wood. For persistent or recurring fungal growth, follow up with the GK Concentrated Fungicidal Wash.

Can I use a decking cleaner on composite decking?

Our GK Multi-Surface Cleaner & Sanitiser is suitable for composite and plastic decking. The GK Decking Cleaner only kills organic material, and is safe to use on any hard surface.

Do I need to pressure wash decking as well as use a cleaner?

Pressure washing and chemical cleaning work well together. Applying a cleaner for decking first and allowing it to dwell and break down algae and biological growth makes subsequent pressure washing more effective and reduces the risk of damage from high-pressure water alone on softwood. Many customers treat first, then rinse with a pressure washer for the best finish.

How do I revive grey, weathered decking?

Greying is caused by UV exposure and surface weathering of the timber fibres. GK Wood Restorer is our decking cleaner and reviver for this specific problem as it opens up the grain and restores the natural colour of the wood, and is ideal as a preparation step before re-oiling or re-staining.

Is it safe to use decking cleaner around plants and garden borders?

Care should be taken with any chemical treatment near planted areas. We recommend watering surrounding borders before and after application to dilute any runoff. Check individual product data sheets for full guidance.