How to Stop K Rend Going Green in 5 Easy Steps

How to Stop K Rend Going Green in 5 Easy Steps

Green render can be extremely frustrating to homeowners, especially when you have light coloured walls. It can cause your rendered walls to be an eyesore, which can be upsetting for the otherwise house-proud amongst us. But what can be done to stop it?

We know it is impossible to shield the outside walls of your home from the environment and harsh weather conditions, which leaves them vulnerable to the growth of unsightly, green biological matter. However, there are ways to tackle the green, improving the appearance of your render and home, and with regular maintenance, even prevent the growth from coming back.

Why is My Render Going Green?

The green colour of your render is caused by the growth of organisms also known as biological growth. Organisms such as mould, moss, lichen and fungus, or more commonly, algae, love to reproduce on your walls to form that stubborn green layer.

Algae is most likely to be the cause of your issues. Airborne algae spores land on exposed, hard surfaces, take up residence, and reproduce at rapid rates. They especially love areas affected by moisture, and if you have any hairline cracks in your render then the cracks will be sure to provide the perfect breeding ground for algae.

Moisture may come from rainfall, or leaks from cracked gutters and blocked drains. Also, if your render is not exposed to much sunlight then the lack of surface water evaporation may encourage the growth of green algae. Another suspect for K Rend discolouration is mould. Mould loves to settle on hard surfaces that suffer from moisture, causing green staining.

No matter what organism is responsible for your K Rend going green, the good news is that the growth is not harmful to your render. You can remove it with a few cleaning methods.

How Do I Remove Green Algae from My K Rend?

Steam Cleaning

You can remove all types of biological growth by utilising steam cleaning. This method sees the removal of algae with extremely hot steam, usually around 150 degrees celsius, as this will kill the organisms effectively, without damaging the render.

Carefully remove the biological growth with a very low pressure wash after steaming. You will need to hire a specialist cleaner for this method to make sure the process is delivered properly and safely.

Without expert guidance you could risk harming the integrity of your render or K Rend.

Algae Remover

The most effective method to remove algae is to use an algae remover product. These products are a biocide that can be applied to the affected area to kill the organisms and remove organic and microbiological soiling.

We recommend using our GK Greener Kleener treatment as it eliminates 99.9% of bacterial growth and will remove mould, lichen and algae.

Solvent, bleach and acid free, our algae remover will not alter the colouration of the treated surface, and with a virtually neutral PH level of 6, once the treatment is dry you do not have to worry about any adverse effects on children or pets.

5 Steps to Stop K Rend Going Green

Once you have your algae remover product to hand, you can remove all biological growth from your render and, with scheduled, regular cleaning, keep it gone for good.

1. Put on Protective Gear

Biocides contain chemicals that could cause irritation to skin or damage to eyes. Make sure to wear protective gloves and safety glasses to reduce risk.

2. Dilute the Algae Remover

The dilution required will depend on the severity of the biological growth. Our GK Greener Kleener requires 2:1 dilution with water for heavy soiling and 3:1 dilution with water for light - medium soiling.

3. Carry Out an Initial Test

Always carry out a test first to ensure compatibility and performance for an acceptable end result. We recommend applying the product on a small, hidden portion of the surface.

4. Apply the Product

Make sure your external surface is dry, then you can apply the product with a brush or spray. For the best results, use a broom or mechanical scraper to remove excess, bulky growth before applying the product. Leave the product to work, ideally overnight.

5. Repeat the Process

In order to stop the algae from returning, we would advise having a cleaning schedule. Depending on the severity of the problem, repeat the process every 6 - 12 months.

Can Common Household Products, Like Vinegar, Baking Soda and Bleach, Remove Green Algae from My K Rend?

If you would prefer a natural solution for removing green algae from your render, then a mixture of vinegar, baking soda or bleach with water will work.

However, it is important to note that these methods will not be as effective as an algae remover product, and they may cause discolouration to the render.

Can Jet Washing Remove Green Algae from K Rend?

Jet washing at a high pressure will remove green algae, however, it could cause damage to your K Rend. The lowest setting may be appropriate, but this removal method is of a higher risk than using specialist products.


Green algae is the most common cause of discoloured, green render. Algae will not harm your property, but can be unsightly, so cleaning the K Rend is advised. While you can use different methods to clean green algae, in order to not damage the render or cause harm to yourself we recommend using our GK Greener Kleener.