The ultimate guide to removing moss, algae and lichen
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How to Clean Paving with Sodium Hypochlorite - The Ultimate Guide to Removing Moss, Algae and Lichen
Paving slabs, patios, block paving and other hard surfaces naturally accumulate algae, moss, lichen and dirt over time. This not only makes outdoor areas look tired, but also creates slippery and unsafe surfaces.
One of the most effective solutions for cleaning paving is sodium hypochlorite, a professional-grade cleaning chemical widely used in exterior cleaning.
In this guide, we’ll explain what sodium hypochlorite is, why it’s so effective for patio and paving cleaning, and how to use it safely for professional-looking results.
What Is Sodium Hypochlorite?
Sodium hypochlorite is a chlorine-based cleaning solution commonly used in exterior cleaning products. It is highly effective at killing organic growth and removing staining caused by biological contaminants.
Unlike pressure washing alone, sodium hypochlorite attacks the root cause of organic growth, helping reduce regrowth over time.
When applied correctly, it can eliminate:
- Algae
- Moss
- Lichen
- Mould
- Organic staining
Professional cleaners regularly use products such as ProClean Moss and Algae Cleaner to restore patios, driveways and paving surfaces quickly and effectively.
Why Use Sodium Hypochlorite on Paving?
Cleaning paving with sodium hypochlorite offers several advantages over standard cleaning methods.
Kills Organic Growth at the Root
Pressure washing may remove visible dirt, but it often leaves algae spores behind. Sodium hypochlorite helps kill the growth completely, reducing the speed of regrowth.
Restores the Appearance of Paving
Organic staining can make paving look old and neglected. Sodium hypochlorite helps restore the original colour and brightness of paving slabs and block paving.
Improves Patio Safety
Algae and moss create slippery surfaces that can become dangerous in wet weather. Removing this growth helps make patios and pathways safer underfoot.
Reduces the Need for Aggressive Pressure Washing
Because sodium hypochlorite breaks down organic growth chemically, excessive pressure washing is often unnecessary. This can help protect more delicate paving surfaces from damage.
Tools and Materials You’ll Need
Before starting, gather the correct equipment for safe and effective application.
Essential Tools
- Pump sprayer or low-pressure applicator
- Pressure washer
- Soft broom or brush
- Bucket
- Clean water supply
- Safety goggles
- Gloves
- Respirator mask
- Protective clothing
Recommended Cleaning Product
For professional results, use a high-quality sodium hypochlorite cleaner such as:
You can also explore our full range of landscaping products for paving preparation and maintenance.
Step-by-Step Guide to Cleaning Paving with Sodium Hypochlorite
Step 1: Prepare the Area
Begin by sweeping away loose dirt, leaves and debris from the paving surface.
If required, carry out a light pressure wash beforehand to remove heavy surface dirt.
Wet surrounding grass, plants and borders thoroughly to help minimise the risk of chemical damage.
Step 2: Dilute the Sodium Hypochlorite
Most paving cleaning applications use a dilution ratio between 1:5 and 1:10, depending on:
- The strength of the product
- The severity of algae or moss growth
- The paving material being treated
Always follow the manufacturer’s instructions carefully and carry out a small test patch before full application.
Never mix sodium hypochlorite with other cleaning chemicals.
Step 3: Apply the Solution
Apply the solution evenly across the paving using a pump sprayer or low-pressure applicator.
Avoid windy conditions and overspray onto surrounding surfaces.
Step 4: Allow the Product to Dwell
Leave the solution to work for approximately 10–30 minutes.
During this time you may notice:
- Algae turning brown or white
- Lichen bleaching and loosening
- Black spots beginning to fade
Do not allow the product to dry fully on the surface.
Step 5: Rinse Thoroughly
Rinse the paving thoroughly with clean water.
If required, use a light pressure wash to remove dead organic matter and remaining residue.
In most cases, aggressive pressure washing is unnecessary once the growth has been killed.
Is Sodium Hypochlorite Safe for Paving?
When used correctly, sodium hypochlorite is safe for most common paving materials, including:
- Concrete slabs
- Block paving
- Sandstone
- Limestone
- Porcelain paving
However, incorrect use can potentially cause:
- Damage to surrounding vegetation
- Fading of jointing sand
- White residue if left to dry on surfaces
Always test a small, inconspicuous area first, particularly when working with natural stone.
Environmental and Safety Considerations
Sodium hypochlorite is highly effective but should always be handled responsibly.
- Prevent runoff into drains, ponds or watercourses
- Keep pets and people away during application
- Rinse surrounding plants thoroughly after use
- Store chemicals safely and out of direct sunlight
Once diluted and rinsed away, sodium hypochlorite naturally breaks down into salt and water over time.
Pressure Washing vs Sodium Hypochlorite Cleaning
Pressure washing alone often removes visible dirt without fully killing algae spores and organic growth.
Sodium hypochlorite treats the underlying cause of staining and biological contamination, helping paving stay cleaner for longer.
For best results, many professionals combine:
- Sodium hypochlorite treatment
- Light pressure washing for final rinsing
Final Thoughts
Sodium hypochlorite remains one of the most effective solutions for removing algae, moss, lichen and organic staining from paving.
Used correctly, it delivers fast, visible results while helping reduce future regrowth and restore the appearance of patios and driveways.
Whether you’re a homeowner refreshing your patio or a professional exterior cleaner, ProClean Moss and Algae Cleaner provides a reliable and cost-effective solution for professional paving cleaning results.