How to Clean and Remove Moss on Decking


Maintaining a clean deck is essential to enhance the longevity of your outdoor space and ensure it remains a safe and enjoyable place for relaxation and entertainment. Moss and algae can create a slippery and unsightly surface, becoming hazards that detract from the beauty and functionality of your garden decking. To address this issue, regular cleaning and moss removal are necessary. Understanding the correct methods and precautions to take before embarking on this maintenance task will not only protect your decking but also make the process more efficient.

Choosing the appropriate cleaning agents and techniques is crucial for effectively removing moss and algae. With a variety of options available, from homemade solutions to specially formulated decking cleaners, it is important to select a method that is not only effective but also environmentally friendly. Moreover, after the initial cleaning, applying the right deck conditioning treatments can prevent future growth of moss and algae. By employing these strategies, you can preserve the quality and appearance of your decking, ensuring it remains an inviting component of your garden for years to come.

Things to consider

  • Regular cleaning prevents hazards and preserves your deck.
  • Select environmentally friendly agents for moss removal.
  • Conditioning treatments help to prevent future growth.

Safety Precautions and Preparations

Before tackling the task of cleaning moss from your decking, it’s pertinent to take the necessary safety precautions and make the right preparations. This ensures not only the efficiency of the task but also the protection of your deck, garden, and personal well-being.

Assessing the Decking Condition

Inspect your wooden decking carefully for any signs of wear or damage. If the surface is slippery due to algae or moss, take note of the most affected areas. Checking the condition also helps decide if a pressure washer can be used safely without causing harm to the wood.

Gathering Necessary Tools and Materials

Compile all the tools and materials you need in advance. This will typically include:

  • A broom for sweeping off loose debris
  • A soft-bristled brush for gentle cleaning
  • A pressure washer (optional, depending on the decking condition)
  • A garden hose for rinsing away cleaning solutions
  • A suitable cleaning solution that won’t damage the wood or surrounding plants

Protecting the Surrounding Garden Area

The products and tools you use to clean the decking can affect the surrounding garden area. Cover plants and grass with a tarp to shield them from any overspray of cleaning solutions. Be mindful of where runoff goes, keeping the safety of your garden and the environment as a priority.

Personal Safety Gear

To protect yourself while cleaning the decking, wear the following safety gear:

  • Non-slip shoes to prevent falls on wet surfaces
  • Gloves to shield your hands from cleaning chemicals
  • Safety goggles to avoid splashback into your eyes
  • Long-sleeved clothing to protect your skin from irritants

Remember, taking these precautions not only safeguards your decking but also ensures you can enjoy your yard without any post-cleaning concerns.

Initial Cleaning Steps

Before you start the more thorough cleaning of your decking, it’s essential to carry out some preparatory steps to ensure a clean, effective surface to work on. Let’s take you through the initial stages of cleaning your deck to prepare it for moss removal.

Removing Furniture and Debris

Firstly, you need to clear your deck. Move all furniture, plant pots, and any other items off the decking to ensure a clutter-free area. Check for any weeds or dirt and debris that might have accumulated around the deck, and remove these as well.

Sweeping the Deck Surface

Using a sturdy broom, sweep the entire surface of your deck to remove loose debris like leaves and twigs. Giving the deck a good sweep ensures that you won’t have unwanted materials getting in the way during the washing process, and it helps to dislodge dirt that’s started to build up.

Initial Rinse with Water

Once the deck is clear and swept, you should give it an initial rinse with water to wet the surface and soften any accumulated grime. At this stage, a normal garden hose is usually sufficient. Avoid using pressure washers at this point, as the powerful stream can damage the wood if not used properly.

Choosing the Right Cleaning Agent

Selecting an effective cleaning agent is crucial for effectively removing moss from your decking. The choice boils down to natural solutions that may be gentler on your deck and the environment, and chemical agents that offer robust cleaning power for tougher jobs.

Natural Cleaning Solutions

Vinegar: A solution of white vinegar and warm water can serve as an eco-friendly option. Apply the mixture to your decking, allow it to sit, then scrub and rinse.

  • Pros: Non-toxic, safe for pets and plants
  • Cons: May require multiple applications for heavy moss

Baking Soda: Sprinkle baking soda on damp decking, then scrub with a brush. This abrasive substance can help in lifting moss, especially when combined with vinegar.

  • Pros: Readily available, gentle on surfaces
  • Cons: May need to be reapplied for stubborn areas

Chemical Cleaning Agents

Bleach: A diluted bleach solution can be used for more persistent moss but handle with care and protect surrounding vegetation.

  • Instructions: Mix 1 part bleach to 4 parts water.
  • Precautions: Wear protective clothing and rinse thoroughly afterwards.

Decking Cleaner: Commercial decking cleaners are formulated specifically for outdoor wooden surfaces and can efficiently remove moss.

  • Pros: Designed for the purpose, often contain protective additives
  • Caution: Follow manufacturer’s directions carefully.

Laundry Detergent: In a pinch, a solution of laundry detergent in warm water can lift light moss. Scrub with a stiff-bristled broom before rinsing off.

  • Pros: Easily accessible, mild on surfaces
  • Cons: Not as powerful against heavy moss growth

When working with any cleaning solution, always test a small, inconspicuous area first and rinse your decking thoroughly after cleaning to remove any residual cleaner which could harm the decking material or the environment.

Effective Moss and Algae Removal Techniques

Removing moss and algae from your decking is crucial to maintaining its appearance and safety. These organisms can create a slippery surface and degrade the wood over time. Follow these targeted strategies to ensure a pristine deck.

Manual Moss Removal Methods

To manually remove moss from your wooden decking, start by using a soft-bristled brush. This method allows you to gently scrub away the moss without damaging the wood. For the best results, sweep your decking first to remove any loose debris, then proceed with thorough brushing in the direction of the wood grain. It’s essential to be diligent but gentle to avoid scratching the surface.

Pressure Washing Considerations

Using a pressure washer can be effective for cleaning decking; however, it’s vital to use the correct technique to avoid damage. If you decide to jet wash your composite or wooden decking, use a fanning nozzle and a low-pressure setting. This method helps to dislodge moss and algae without harming the decking material. Always keep the nozzle moving to prevent concentrated pressure on any one spot.

Using Decking Cleaners and Solutions

For a deeper clean, consider specialised deck cleaners or create a solution with washing up liquid and warm water. Apply the solution to the deck, let it sit for a few minutes, then scrub gently with your brush. Rinse thoroughly with plain water to clean decking surfaces of any residue. For regular maintenance, incorporating these cleaners in your routine can help prevent the re-growth of moss and algae.

Post-Cleaning Maintenance

After you’ve succeeded in cleaning moss and algae from your decking, maintaining its condition is crucial. Proper post-cleaning maintenance not only prolongs the life of your deck but also ensures it remains safe and aesthetically pleasing.

Rinsing and Drying the Deck

Immediately after cleaning, rinse your deck thoroughly using a garden hose to eliminate any residue from cleaning agents. For a composite deck, ensure you use a gentle stream to prevent damage. If you have a wooden deck, avoid using high pressure that could cause splintering. Allow the deck to dry completely, which may take up to two full days, depending on weather conditions.

Assessing for Damage and Repairs

Once the deck is dry, inspect for any signs of damage, such as loose boards or nails, and make necessary repairs. This is also the ideal time to look for continued splintering on a wooden deck or issues with a composite deck. Addressing these problems promptly prevents further deterioration and keeps your deck safe.

Preventive Measures for Moss and Algae

To hinder the growth of moss and algae, consider the application of anti-slip products which often contain algae-inhibiting properties. Treat your deck with decking oil at least once a year to protect the wood and maintain its natural colour. Additionally, keeping your deck clear of leaves and debris will significantly reduce the conditions moss and algae need to thrive.

Deck Conditioning and Stain Application

To ensure a lasting finish and protection for your decking, applying decking oils and stains correctly is crucial, followed by a reliable sealing process. Here’s how you can condition and protect your wooden deck efficiently.

Applying Decking Oils and Stains

After thoroughly cleaning your deck and removing all dirt and debris, it’s time to nourish the wood. Start by selecting a high-quality decking oil or stain that suits your wooden deck’s needs. Decking oils penetrate deeply to replenish natural oils lost through weathering, whereas stains add colour and a protective layer against the elements.

  • Decking Oil:
    • Test the oil on a small, inconspicuous area to ensure it gives the desired finish.
    • Apply the oil with a brush or roller, working along the length of the deck boards.
    • Allow adequate time for the oil to absorb into the wood before applying a second coat if necessary.
  • Decking Stain:
    • Ensure the stain is thoroughly mixed to prevent colour inconsistencies.
    • Use a brush with natural bristles to apply the stain evenly, maintaining a wet edge to avoid lap marks.
    • Wait for the first coat to dry completely before assessing if a second coat is required for uniform coverage.

Sealing for Long-Term Protection

Sealing your deck is the final step in the conditioning process, providing a barrier against moisture, UV rays, and general wear. A sealant can also enhance the overall look of your deck by adding a subtle sheen.

  • Sealant Application:
    • Make sure the stained deck is dry and free from any dust or particles.
    • Apply the sealant with a clean brush or sprayer, ensuring even coverage.
    • Leave the sealant to dry completely, according to the product’s instructions, before using the deck again.

Through vigilant application of oils or stain, followed by a high-quality sealant, your deck will be well-prepared to face the diverse British weather, maintaining its beauty and integrity for seasons to come.

Environmental and Regulatory Considerations

When cleaning and removing moss from your decking, it is crucial to consider both the environmental impact of the cleaning agents used and the regulatory standards that apply to them. Make sure to choose solutions that are as gentle on the ecosystem as they are effective on moss.

Eco-Friendly Cleaning Options

When selecting a cleaning solution for moss on your decking, considering products that minimise ecological harm is key. Natural alternatives like vinegar can be an effective way to tackle moss. Diluted vinegar, applied and scrubbed over the affected areas, can help remove moss without the use of harsh chemicals. This approach ensures that run-off will not harm your garden’s plants or the surrounding environment.

Understanding Ipso Regulations and Standards

Decking cleaners should be compliant with Ipso regulations and standards, which help to prevent environmental damage and ensure the safety of the products for users. It’s your responsibility to verify that the products you’re using on your decking are Ipso regulated. These products have been assessed for environmental and health impacts, ensuring that they meet rigorous safety criteria.

Frequently Asked Questions

In addressing the challenges of moss and algae on your decking, these FAQs will guide you through the most effective methods, natural solutions, and preventative measures to ensure your deck remains clean and safe.

What are the most effective methods for eradicating green mould from wooden surfaces?

Manual scraping followed by washing with a specialised deck-cleaning solution is highly effective in removing green mould from wooden surfaces. For minimal damage to the wood and thorough cleaning, a soft bristle brush or deck cleaner can be used.

Can household vinegar be utilised to exterminate algae on deck surfaces?

Yes, diluted white vinegar can serve as an environmentally friendly option to eliminate algae. Vinegar’s acidity breaks down the structure of algae without damaging the decking material.

What are the premier commercial products available for algae removal on decks?

There are various commercial deck cleaning products designed to target algae and moss. Look for products that are formulated specifically for use on decks, such as those containing anti-mould chemicals to ensure their effectiveness and safety for use on wooden surfaces.

How can one prevent the recurrence of algae and moss on decked areas?

Regular maintenance, including keeping the deck dry, ensuring proper drainage, and trimming back overhanging vegetation, effectively prevents algae and moss growth. Additionally, applying a preventative treatment with an anti-fungal agent can offer long-term protection.

What homemade solutions are recommended for the removal of algae on decking?

A mixture of one part white vinegar to one part water can be applied to the affected areas. For a more potent solution, baking soda or a mixture of oxygen bleach can be used as an alternative to chemical cleaners which is cost-effective and less harsh on the environment.

What are the best practices for cleaning decking in a natural and eco-friendly manner?

For an eco-friendly approach, utilise natural cleaners such as vinegar or baking soda solutions. Scrubbing with a soft bristle brush to protect the wood and rinsing with water ensures a gentle yet effective cleaning process. Regular sweeping and keeping the area free from debris also reduce the need for harsh chemicals.

About the author 


Hey there, I am founder and editor in chief here at Good Grow. I guess I've always known I was going to be a gardener. I'm on a mission to share my UK based weed control & lawn care tips with you all. If you have any queries please post in the comments below.

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