April 12th, 2023 by Shauna Hammond

What is blackspot?

Lichen but more commonly referred to as Black spot is a common problem that can affect patios and other outdoor stone surfaces. These issues not only look unsightly, but when left untreated they can also damage the surface over time. In this blog, we will explore the effects of lichen on patios and provide some tips for not only treating it but how you can look to prevent it from forming in the future too!

How to tell if my patio has blackspot?

It’s incredibly easy to tell if your patio is suffering from an invasion of blackspot since it is not a disease that stays hidden. As the name suggests black spots on the surface will appear as unsightly dark splotches that spread across the surface of patios and pavements. They are not particularly fussy about where they lay root either, so there is no particular type of stone that is more or less resistant unfortunately.

You will also be able to tell if the marks on your patio are black spots or simply dirt by the fact that lichen forms a protective and hard-wearing crust which is visible and also makes it incredibly difficult to remove. You can tire yourself out all day long scrubbing or blasting these marks with a pressure washer and they still won’t budge – so if you have noticed dark markings that will not move regardless of your efforts then there is a good chance that lichen has made itself at home.

How can it affect my patio?

As mentioned above, black spot, unfortunately, doesn’t just look unsightly – as well as ruining the look of your patio if left untreated it can begin to cause damage to your stone slabs that is because the fungus can eat away at the surface of the patio, causing it to deteriorate over time. This can lead to cracks and other damage that can be costly to repair - although not to worry too much it can take a long time before it degrades to this point, however, it’s definitely worth keeping on top of it just to be sure! In addition to the threat of damage, black spots can make the patio slippery and dangerous to walk on, especially during wet weather.

How do I treat black spots?

If you've already got a case of black spot, clean up any debris currently on your patio with a pressure washer or similar tool so that there's nothing left behind for new spores to grow on once they appear again during warmer weather (which they will). Once the patio is dry it’s time to treat it – as mentioned you can’t remove black spot simply by scrubbing – you need to use lichen treatments they contain a powerful cleaning agent known as Sodium Hypochlorite (That’s a very strong bleach to me and you!) this active ingredient is powerful enough to break down lichen so that it can be then easily rinsed way. However, it is very important to use caution while applying these products as they can cause damage to plant and aquatic life so be careful to avoid these areas when applying.

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Can I prevent it from coming back?

Once you have finally managed to get rid of the black spot, you might be wondering how you can make sure that it doesn’t come back, especially after all that hard work. Well while there is no sure-fire way to keep it at bay, patios that are well-maintained and kept clean are less likely to suffer from invasion by lichen. That’s why it is very important to keep your patio clear of debris such as fallen leaves by regularly sweeping – also make it a routine to use patio cleaners or pressure washers to stop the build-up of dirt and grime. You can also use a mixture of water and bleach (1 part bleach to 10 parts water) to clean your patio once a month in order to prevent lichen from spreading.

We hope that with this blog you better know how to spot when black lichen begins to form on your patio and how it can be treated in order to keep your patio looking its best!