Your roof isn’t something you think needs cleaning. However, you should clean it if you want it maintained and to ensure a long lifespan. After a flat roof installation, you should ideally clean it every 12 to 24 months. If you want to get the best out of your flat roof, here are some different methods you can use to keep it looking good.

Pressure Washing

Pressure cleaning is a popular method to clean outdoor areas and structures because it’s practical and straightforward. Pressure cleaning is also an option that cleans your roof correctly and doesn’t pose a problem for the health of the environment. While using water spraying at a high-pressure, the grime looks like it’s being peeled away. It uses almost ten litres of water per minute but removes even the toughest dirt including algae, moss and lichen without needing chemicals or detergents.

Chlorine Cleaning

Although this uses a chemical, chlorine cleaning is a faster method of cleaning your roof in comparison to using a pressure washer. This also means that there will be less time spent walking on your roof – whether you’re doing it yourself, or getting a professional cleaning company to do it for you. The more you walk on your roof, the less wear and tear you’ll have to deal with in the future. However, because this method uses chlorine, you should be aware that the chemical can be dangerous around people, animals, and the surrounding environment. Take full safety precautions or, ideally, contract professionals to do this for you.

Sodium Hydroxide

Sodium Hydroxide is another chemical that is just as effective as chlorine. Unfortunately, it has two negative factors that you should keep in mind should you choose this route when cleaning your flat roof. The first of the two drawbacks is that if you use sodium hydroxide on your roof, you’ll need to rinse it thoroughly afterwards, which will use a lot of water. The other drawback is that if too much sodium hydroxide is used, or the amount is too concentrated, it will cause irreparable damage to your roof. Therefore, sodium hydroxide must be used carefully and sparingly, ideally by a professional.


Your roof needs to be maintained – even if its installation was less than two years ago. This includes cleaning it at the appropriate intervals. Make sure you choose the best option for you, out of these four different methods, so your roof keeps looking good for a long time to come.

For information and advice on the best way to clean your particular flat roof, contact our specialist team on 0800 456888.

Also, check out our Flat Roof Guide.

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