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How to Clean Black Spots From Your Patio : Step by Step

In this blog we are going to look at how to clean Natural Stone Patio Slabs and return them to looking brand new. Graham and Emily purchased Mint Indian Sandstone paving slabs eight years ago and over time the slabs had discoloured very badly with black spots, lichen and other vegetation. 


Their maintenance regimen up to this point had been to wash the patio down with a Powerhose once a year. Due to lockdown they were spending a lot more time entertaining in their garden and were disappointed with how the patio looked.

Porous vs Non Porous Paving Slabs - How porous are your paving slabs?

There are a few main types of paving slabs commonly used in gardens and patio areas today, starting with Porcelain which is the hardest type of material and is non-porous at the opposite end of the scale is Sandstone, which is one of the most porous natural stone materials. 


Porous paving slabs allows rainwater to soak in the porous surface and are a hotbed for lichen stains and black spots to take hold on your patio. 


Fortunately this problem can be easily rectified with a good cleaning product. It does not need a professional cleaner to clean it off. You can DIY with Black Spot Remover.


Porcelain vs. Natural Stone Paving. Which is Better? Read our blog here to understand what is the difference between porcelain outdoor tiles, limestone,  sandstone and granite paving slabs.

Stontex Black Spot Remover

We receive this question everyday: How to clean patio slabs? And the answer is simple, find the right professional cleaning product and DIY.


Stontex Black Spot Remover is a professional grade outdoor cleaner which eliminates all traces of stubborn grey lichen and black spots from all masonry and stone surfaces. This one off treatment eradicates black spots and algae with ease.


Black spot removed is a professional outdoor cleaning that removes stubborn aged black and grey lichen algae spots from all mansory and natural stone surfaces. It’s suitable for Professional and DIY use. Black spot remover also removes red and free algae, reviving the surface to its original appearance. It’s a ready-to-use cleaner, easy to use. Keep reading below to learn how to use black spot remover.


Black Spot remover works very well on Porcelain, Limestone, Sandstone paving slabs and brick or masonry surfaces.

How to use STONTEX Patio Black Spot Remover

Check out this how-to-use Black Spot Remover video.


To clean your patio you will need:

• STONTEX Black Spot Remover 5l

• A Yard Brush

• A Power Washer or a garden hose with a high-pressure head.


1) Remove any loose vegetation from the patio area and WET your patio

2) Apply neat Black Spot Remover to your patio

    • Use a watering can rose if you have one to spread the Black Spot Remover evenly.

    • 1 litre of Black Spot Remover should cover 5m2 of patio.

3) Brush the patio with a yard brush to work the Black Spot Remover into the patio

4) Allow Black Spot Remover to soak in the patio for 2 hours.

    • For very heavily stained areas follow step 1 to 3 again but leave the product on the patio overnight before washing it off.

5) Clean the patio with a power washer


Be careful not to damage the grout with the power washer.

Black Spot Remover can be bought on our website (click here).  We deliver nationwide in 2-3 days. Order now and get your patio looking as good as new!

Blog by Calum

Tile Merchant


Cal Bannerman is a freelance writer, editor, podcaster and voice actor from the Scottish Borders. They run the storytelling podcast “Stories from the Hearth”, and live in a wee Glasgow flat with their partner and cat.