How to Remove Black Spots From Patio Slabs, Stones, and Tiles: A Step-by-Step Guide

Introduction

In Ireland’s unpredictable and often miserable climate, it’s no surprise that black mould and black spots can grow on natural stone paving slabs and outdoor tiled patios. Removing black spots from patio stones, slabs an tiles can be challenging if you don’t have the right cleaning products or the right techniques.

In this step-by-step guide to cleaning black spots on paving slabs, we’ll walk you through the different types of paving slabs and how cleaning instructions differ from one to another.

We’ll also discuss a variety of cleaning products and cleaning techniques to help you remove black spots from patios, driveways, garden paths, porch steps and more.

Here at Tile Merchant, we stock a wide range of natural stone paving slabs—from granite to limestone and sandstone—so we know just how important it is for our customers, all across Ireland, to be able to maintain the natural freshly-laid look of their patio slabs.

Read on to discover how to remove black lichen and black spots from a variety of patio materials!

Porous vs Non-Porous Paving Slabs: How Porous Are Your Paving Slabs and Why Does it Matter?

‘Porosity’ is the degree to which a material—in our case, natural stone paving slabs and patio tiles—lets in moisture through ‘pores’, or microscopic holes, in the surface of the material.

The more porous a substance, the more rainwater can gather and soak into it. With outdoor paving stones and porcelain tiles, a porous slab means a much higher chance of black lichen and mould growing on your lovely patio, driveway or garden path.

This is why it’s worthwhile knowing the difference between porous and non-porous outdoor paving materials.

More porous materials, like sandstone and limestone, will require regular annual sealing and careful cleaning to remove any build-up of grime, mould, and/or lichen.

On the other hand, non-porous materials like our Ireland-famous 20mm outdoor porcelain tiles are unlikely to accrue mould or any other kind of black spots.

Porcelain tiles don’t need sealing and are far easier to keep out-of-the-box clean, compared to natural stone.

Granite paving slabs act as a sort of in-between: not as porous as sandstone and limestone, but still more porous than porcelain.

Thankfully, whatever you choose to install for your garden patio—even if it is highly porous sandstone or limestone—we’ve got all you need to keep your outdoor paving installations looking fresh and fantastic for many, many years to come! Read on to find out how to remove black spots from paving stones.

How to Remove Black Spots From Paving Slabs: 3 Techniques

Removing black spots from patio and paving slabs can be a total nightmare if you’re unprepared, but with our three tried-and-tested cleaning techniques, we’re confident you’ll have your patio looking sparkling brand new in no time.

Before you begin cleaning your outdoor space we advise that you remove all your plants and outdoor furniture. You should also brush any dirt from your patio and removed any weeds that might be present. These are solid foundational steps for cleaning any type of natural stone slab or outdoor tile.

Cleaning Method 1) White Vinegar and Water

It might sound too simple to be effective, but the classic cleaning hack of diluted white vinegar can actually prove to be the best homemade patio black spot remover, capable of removing some of the less stubborn cases of black lichen, black spots, and black mould from your patio.

Step 1: Prepare The Area And Your Cleaning Solution

Once you’ve cleared the area you intend to clean, create a solution with a 50:50 ratio of distilled white vinegar to water. 

Step 2: Apply The Solution

Once have your solution ready, pour it onto your patio, ensuring it is spread evenly and covers the entire patio area.  

Step 3: Leave The Solution To Work On The Black Marks And Remove

Allow the solution to sit on the natural stone slabs for approximately 20-25 minutes. After allowing the solution to soak in to the surface, scrub the area with a brush.

Step 4: Rinse and repeat

Finally, you should rinse your paving area with warm water to remove the solution and, with any luck, the black mould. If some of the mould comes away but not all, you can either repeat steps 1-4, or try a more heavy-duty cleaning product like Stontex Black Spot Remover (described below).

Once these steps have been completed you can put all your garden furniture back to its original place and you can relax and enjoy your garden!

Cleaning Method 2) Power Washing Your Natural Stone Patio Safely

The quickest way to clean your patio is to use a power-washer. However, because this is a quick-fix option, caution is advised when using this method as the high water pressure does have the potential to cause damage to your patio, paving and especially your outdoor grouting.

Step 1: Prepare The Area

Prepare the area as described above, by clearing it of furniture and plants and sweeping the area free of other debris.

Step 2: Begin Power-Washing Your Patio

When using a power washer to clean black spots off patio and paving slabs, you should always start at a low setting to reduce the risk of damaging your patio area. Be extra careful when washing grouted areas of your patio, as these sections are more prone to be damaged by high pressure.

Step 3: Repeat If Necessary Or Use A Heavy Duty Cleaning Product

If power-washing your patio has entirely cleaned it and removed all the black spots, mould and lichen from it, then you can now sit back and relax! If, however, power-washing didn’t finish the job, it’s time to consider a heavier-duty cleaning product like Stontex Black Spot Remover.

Cleaning method 3) Using Stontex Black Spot Remover For Patio Cleaning

Here at Tile Merchant, our customer service team hears the same question almost every day: What are the black spots on my patio slabs? And, how to remove black spots on patio slabs?

Thankfully, the answer is simple: those black spots are either black mould or lichen, a totally natural build-up. And removing black spots from patio stones and slabs is easy, all you have to do is first find the right professional cleaning product: Stontex Black Spot Remover.

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, and is suitable for both professional and DIY use.

Black spot remover also removes red and green algae from your patio, helping you to revive the surface to its original appearance. Black Spot Remover from Stontex is a ready-to-use and easy-to-use cleaning product, and is suitable for porcelain, limestone, granite, concrete, sandstone, marble and more.

Read on to learn how to use black spot remover to completely clean your patio.

How to use Stontex Patio Black Spot Remover to Clean Your Patio

Check out this how-to-use Black Spot Remover video and follow along for the best way to remove black spots from your patio. Our video tutorial provides a simple and effective solution to remove them.

If you’d rather follow written instructions instead, follow our step-by-step guide below, and restore your garden paving slabs to their former glory. Don't let black spots ruin the beauty of your outdoor space any longer.

To clean your patio you will first need:

• STONTEX Black Spot Remover 5l
• An outdoor brush
• A power-washer or garden hose

Here is our step-by-step guide to cleaning your patio or driveway with Stontex Black Spot Remover:

• Remove any loose vegetation from the patio area and make sure your patio is wet by spraying it with a hose (or waiting for it to rain, which in Ireland shouldn’t be long!).
• Apply the undiluted Black Spot Remover solution to your patio by:
  • Using a watering can to spread the Black Spot Remover evenly.
  • Using 1ltr of Black Spot Remover per 5m² of patio.
• Brush the patio vigorously with to work the Black Spot Remover into the stone slabs.
• Allow the Black Spot Remover solution to soak in the patio for at least 2 hours (or for heavily stained areas, leave overnight).
• Finally, give your newly cleaned patio a thorough wash to remove all of the solution and the now-dead lichen using a hose or power washer.

Note: If you use a power-washer, set it to a low pressure and be especially careful around your patio’s grouting.

Black Spot Remover can be bought on our website (click here).  We deliver nationwide in 2-4 days. Order now and get your patio looking as good as new!

Conclusion

If you’ve been wondering what those black marks on your outdoor paving slabs, patio, or porcelain tiles are, the answer is black mould or lichen. Thankfully, removing black spots from patios is fairly straightforward.

Use one of our three patented methods to effectively and efficiently remove black lichen from concrete, natural stone, or tiles in as little as an hour or two.

For tougher stains and large areas of black mould and lichen, be sure to remove the black spots from patios by applying a heavy-duty cleaner like Stontex Black Spot Remover, available for Ireland-wide delivery from Tile Merchant in just 2-4 working days.

Shop the full range of paving cleaning solutions on the Tile Merchant website, or learn more about outdoor installation, cleaning tips and maintenance by following the Tile Merchant Style & Advice blog.

Why Tile Merchant?

We offer extremely competitive pricing on our entire range of tiles and likewise. We stock a huge range of wall and floor tiles and our prices are competitive for retail and trade. Our stock is widely available in our tile stores in Dublin and Ashbourne (Co. Meath) which are open 7 days a week.

Alternatively, if you’d prefer to shop our tiles online, we can supply you with samples delivered for free.

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