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How to Stop Patio Going Green (Eliminating Algae and Mould)

How To Stop A Patio From Going Green Naturally

A brick paving covered in green moss

Nature has a way of taking over if left unchecked, and patios are no exception. Green algae and moss can quickly build up on stone floors, driveways, fences and patio surfaces, particularly in shady areas with high rainfall and damp conditions with little sunlight and air.

To stop your patio from turning green, you need a multi-pronged approach addressing the root causes of moss, algae, and mould growth.

Ongoing patio maintenance is vital to preventing green paving slabs. Keeping your patio clean and debris-free’ll reduce the chances of algae and moss finding a foothold in your outdoor space.

Additionally, improving sun exposure and upgrading drainage systems can help keep your patio dry, discouraging the growth of green algae and mould.

Understanding The Causes Of A Green Patio

Before diving into the best long-term solution for removing algae, it’s essential to understand the main culprits behind concrete areas or a patio going green:

  • Excess moisture,
  • Insufficient sunlight
  • Poor drainage.

These factors create the perfect breeding ground for green algae and mould, leading to unsightly green deposits, slip hazards, and potential damage to your patio paving surface.

To stop moss and remove the green mould, you need to address the underlying issues; by doing this, you will effectively prevent algae and mould growth on your patio, ensuring a clean and inviting outdoor space for years to come. Let’s take a deep dive at each of the factors that cause the main problem of green mould problems on patios.

Excess Moisture

Excess moisture is the primary driver of green algae and mould growth on patios. Damp conditions create an ideal place for these organisms to thrive, leading to the proliferation of green algae growth on your patio surface. Signs of excessive moisture may include the presence of green algae and mould, as well as dampness and discolouration of your fencing and patio.

To reduce excess moisture in humid areas on your patio, consider improving drainage, using a dehumidifier, or covering the patio when not used. Frequent cleaning and maintenance can help keep your patio dry and prevent the buildup of moisture that can lead to algae and mould.

Insufficient Sunlight

Insufficient sunlight is another major cause of green patios. Algae and mould thrive in damp, dark conditions, so a lack of direct sunlight can encourage growth on your patio. This can lead to discolouration and damage, making your outdoor space less inviting for relaxation and entertainment.

To enhance sunlight exposure on your patio, consider removing obstructions blocking the sun, such as trees or buildings. Additionally, using reflective surfaces can help increase the amount of sunlight that reaches your patio, further discouraging the growth of green algae and mould.

Poor Drainage

Poor drainage is the third major factor contributing to green patios. Inadequate drainage can lead to water accumulating on your patio and water underneath, creating damp conditions that promote algae and mould growth. This can damage the patio material, erosion of the surrounding soil, and even structural damage to your home’s foundation.

To improve drainage on your patio, consider installing a sound drainage system specifically designed to move water away from the patio, such as a French drain. Additionally, grading the patio area to ensure proper water runoff is crucial.

By addressing drainage issues, you can help keep your patio dry and prevent the growth of harmful green algae and mould.

How To Remove Green Algae From Patio Slabs

Now that we understand the causes of green patios, let’s explore the several methods and the most effective ways to remove green algae and mould from your patio stones. Pressure washing is a popular method for eliminating green growth, but it must be done cautiously to avoid damaging the patio surface.

Eco-friendly cleaning solutions, such as white vinegar, acid and baking soda, can also effectively remove green algae and mould.

Commercial cleaning products are available for more stubborn stains to help you tackle the problem but be careful because they can be dangerous if spilt. No matter your chosen method, following proper procedures and safety precautions is essential to ensure the best results and protect your patio from damage.

Pressure Washer

Someone using a power washer on a patio

Pressure washing, or power washing as some call it, is an excellent way of removing green algae from walls and patio paving. Using a high-pressure stream of water, pressure washers can effectively blast away algae, mould, and other contaminants from your patio surface. However, improper use of pressure washers can damage concrete or stone, so it’s crucial to follow the manufacturer’s guidelines and use the correct pressure settings. This page lists the correct steps on how to jet wash a patio.

When choosing power washers for your patio, look for one with adjustable pressure levels and a PSI of approximately 1000 to 1500. Popular pressure washer options include the Kärcher K4 Power Control and the Sun Joe SPX3000 XT1. These are all excellent algae removers.

Test it on a patio section before tackling the entire surface with the power washing tool to ensure you won’t cause any damage.

Eco-friendly Cleaning Solutions

For a more eco-friendly approach to cleaning your patio, consider using natural patio solutions like vinegar, bleach or baking soda using a garden sprayer. To use vinegar, mix equal parts of white vinegar and water, then pour the solution over your patio slabs. Wait a few minutes, then scrub the surface with a stiff-bristled brush to kill green algae.

Baking soda is also a good alternative for patio slabs by mixing it with warm water and pouring them onto the pavers or simply spray using a garden sprayer. You have to scrub with a stiff-bristled brush and rinse the area thoroughly with water.

Vinegar and baking soda effectively remove algae and mould and won’t harm your garden plants or the environment.

Commercial Cleaning Products

Commercial garden paving cleaning products can effectively solve more stubborn algae and mould stains. These specially formulated products are designed to remove algae, dirt, grime, and other contaminants from surfaces like patio slabs. Before using any commercial cleaning product, read the instructions before proceeding.

When selecting a commercial algae remover, consider the type of surface you’re working with and the severity of the stains. Sprays, gels, and wipes are all available, each with advantages and disadvantages. Regardless of the algae remover you choose, always have protective clothing on so you don’t get harmed by chemicals, and avoid combining different cleaning products, as this can produce hazardous fumes.

Long-Term Prevention Strategies

While scrubbing your patio can provide immediate results, implementing long-term prevention strategies is the best way to keep algae and mould at bay. Constant maintenance, improving sun exposure, and upgrading drainage systems may be time-consuming, but they prevent green algae and mildew from growing on your patio.

It’s crucial to try and address the root causes. If you notice algae grow and mould growth, you can create an environment less conducive to their proliferation. This saves you lots of effort and helps you maintain a beautiful, safe outdoor space for your family and guests.

Regular Maintenance

To prevent green algae and mould growth on your patio, regular maintenance is needed. This includes sweeping your patio every week and removing any leaves, dirt, and debris that can accumulate and create damp conditions. Additionally, clean your patio periodically using soapy hot water and a stiff-bristled brush, or consider pressure washing if necessary.

Sealing every 3-5 years is another important aspect of regular maintenance. This protective barrier helps prevent water penetration and can inhibit algae and mould growth. By staying proactive with your patio maintenance, you can significantly reduce the chances of green growth taking over your outdoor space.

Improving Sun Exposure

Patios turning green can be a real headache, but enhancing sunlight exposure on your patio can help discourage and get rid of algae and mould growth. If your patio is shaded by trees, buildings, or other obstructions, consider trimming or removing them so your patio gains more sunlight. You can also use reflective materials or surfaces around your patio to increase the sunlight it receives.

Creating a brighter environment and allowing the weather to shine on your patio makes it harder for green growth to gain a foothold in your outdoor space.

Upgrading Drainage Systems

A brickwork patio installation with a tool and drainage

Proper drainage prevents green algae and mould on your patio. Water can accumulate on the surface due to poor drainage, creating damp conditions that promote the growth of these organisms. A French drain may be an option, or try other drainage systems to move water away from your patio to improve drainage.

Grading the patio area to ensure proper water runoff is also essential. Make sure the slope of the patio directs water away from the surface and your home’s foundation. By addressing drainage issues and keeping your patio dry, you can effectively prevent the increase of harmful green algae and mould.

Protective Treatments For Patios

In addition to long-term prevention strategies for patios that keep going green, protective treatments are available to safeguard your patio from green algae and mould. Paving sealants and wood impregnators are two popular options that provide long-lasting protection against green moss and other potential threats to your patio’s appearance and structural integrity.

Investing in protective treatments for your patio lets you enjoy your outdoor space and know it is well-guarded against unwanted green invaders.

Paving Sealants

Paving sealants are an excellent way to protect your garden paving slabs and patio surfaces from dirt, water, and other elements that can cause damage. These sealants create a barrier that helps prevent algae and mould growth, keeping your patio looking clean and attractive.

When choosing a patio paving sealant, look for products specifically designed for outdoor use, such as Smartseal Natural Stone Sealer or Everbuild sealers. To apply the sealant, follow the manufacturer’s instructions and spread through a brush or roller for a thin, even layer. Here’s a step-by-step guide on how to seal paving stones.

The sealant must dry entirely on the patio to ensure the best results. You can also use polymeric sand between the gaps as a way to stop algae from coming through.

Wood Impregnators

Wood impregnators are another valuable protective treatment for patios, particularly those with wooden surfaces or timber decking. These products offer protection from water damage, rot, and discolouration, helping maintain your patio’s beauty and longevity.

When selecting a wood impregnator, choose a product specifically designed for outdoor use, such as ProPERLA Paving Impregnator, Ronseal Multipurpose Wood Treatment, or Cuprinol Wood Preserver Clear. Apply the impregnator according to the manufacturer’s instructions, ensuring your patio is clean and dry before application. 

Does Sealing a Patio Stop Algae?

Based on our experience, sealing is an effective way of preventing and helping get rid of algae growth and grass coming through the patio. It’s also more expensive than just buying a cheap algae killer.

Last Word

Keeping your patio and garden slabs free of green algae and mould is essential for maintaining a clean, safe, and inviting outdoor space. By understanding the causes of green patios and implementing effective cleaning methods, long-term prevention strategies, and protective treatments, you can successfully combat green growth and enjoy a new patio for years.

Don’t let your patio fall victim to ugly and hazardous green algae and mould that will become an eyesore. Take action today with our range of tips to reclaim your outdoor sanctuary.