Render Cleaning Explained – What Causes Green Algae and How to Remove It

If you’ve noticed green, black, or even red staining on your home’s exterior walls, you’re not alone. Many UK homeowners struggle with algae and organic growth on their render — particularly in damp coastal regions like Weston-super-Mare, Clevedon, and North Somerset.

At Top Glass Exterior Cleaners, we specialise in soft-wash render cleaning, a safe and effective method for removing algae, dirt, and weather stains without damaging your property.

This guide explains why algae grows, how it affects your render, and what you can do to prevent it from returning.

What Causes Green Algae on Render?

Green algae forms on rendered walls when moisture, shade, and organic material combine — ideal conditions for algae spores to thrive. Coastal climates and the UK’s wet seasons make the problem even more common.

Main causes include:

• Persistent damp or rainfall on shaded walls.

• Poor air circulation or north-facing facades.

• Leaky gutters or overflowing downpipes.

• Porous render types such as K-Rend or Weber.

• Nearby trees or vegetation trapping moisture.

Without treatment, algae continues to spread, leading to discolouration, deterioration, and costly repainting.

Why Algae Is More Than Just Cosmetic

While algae might first appear as an eyesore, the long-term effects are more serious:

• Surface degradation: Algae traps moisture, weakening the render.

• Staining and discolouration: Affects kerb appeal and property value.

• Mould and mildew: Can spread internally through damp walls.

• Frost damage: Moisture in algae can freeze and crack surfaces in winter.

Regular cleaning is the only way to keep your render healthy and visually appealing.

How Professional Render Cleaning Works

At Top Glass Exterior Cleaners, we use an advanced soft-wash cleaning method, combining low-pressure water and biodegradable cleaning solutions. This process gently removes algae, moss, and grime without harming your render or paintwork.

Our render cleaning process:

1. Inspection & preparation – Assess surface condition and affected areas.

2. Pre-treatment – Apply eco-friendly biocide to kill spores and organic growth.

3. Soft wash rinse – Low-pressure rinse removes residue safely.

4. Post-treatment protection – Apply protective layer to slow regrowth.

Unlike pressure washing, soft washing is non-abrasive and ensures a longer-lasting clean.

Which Render Types Can Be Cleaned?

Our system safely cleans most modern render finishes, including:

• K-Rend

• Weber

• Parex

• Monocouche

• Sand & Cement Render

If your property has a painted finish, we adjust the cleaning strength to protect coatings while removing contamination effectively.

How to Prevent Algae Returning

Once your render has been professionally cleaned, a few maintenance steps can help keep it spotless:

• Ensure gutters and downpipes are clear and leak-free.

• Trim nearby hedges or trees to increase sunlight.

• Rinse walls annually to remove surface dust.

• Schedule a biocide re-treatment every 12–18 months.

At Top Glass, we provide ongoing maintenance plans to ensure your home stays clean all year round.

The Benefits of Professional Render Cleaning

• Enhances kerb appeal and property value.

• Extends the lifespan of your render.

• Protects against moisture and damp damage.

• Safe, eco-friendly, and fully insured service.

• Ideal for homes and commercial buildings.

With years of experience and hundreds of satisfied customers, we’ve become one of North Somerset’s most trusted exterior cleaning specialists.

Local Areas We Cover

We proudly serve:Weston-super-Mare, Clevedon, Yatton, Congresbury, Cheddar, Winscombe, Banwell, and the surrounding North Somerset region.

Wherever you are, our professional team can restore your render’s original colour and cleanliness.

FAQs

1. Will pressure washing damage my render?Yes, high-pressure washing can damage render and force water behind the surface. Soft washing is the safest and most effective option.

2. How often should render be cleaned?Most properties benefit from cleaning every 2–3 years, but shaded or coastal homes may need it annually.

3. Does render cleaning remove black stains too?Yes, soft washing removes both green and black organic staining, as well as atmospheric dirt.

4. Is the cleaning solution safe for pets and plants?Absolutely — our biodegradable cleaning agents are environmentally safe.

5. How long does the treatment last?Typically, 12–24 months depending on exposure and weather conditions.

Why Choose Top Glass Exterior Cleaners

• Fully insured and 5-star rated.

• Friendly, professional, and reliable.

• Eco-friendly soft-wash systems.

• Great value maintenance packages.

• Local experts with excellent customer feedback.

Our results speak for themselves — bringing walls, patios, and driveways back to life.

Book Your Render Cleaning Today

Transform your property with professional render cleaning from Top Glass Exterior Cleaners. Safe, effective, and long-lasting results for every home.

Contact Top Glass Exterior Cleaners

For professional window cleaning, gutter clearing, render and conservatory cleaning, and jet-washing in Weston-super-Mare, contact our friendly local team today.

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Address: Glider Ave, Weston-super-Mare, BS24 8EZ

Tel: 07712 127733

Open Hours: Mon–Fri 9 am – 5 pm | Sat–Sun Closed

Get a free, no-obligation quote and keep your home spotless this January.

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