Cleaning exposed concrete slabs: How to remove green deposits, moss, etc.

Green covering, moss & co.
Cleaning exposed concrete slabs: How to remove stubborn dirt

It is a popular surface for terraces and walkways: exposed aggregate concrete. Although the panels are more robust than other building materials, deposits accumulate on their surface. What is the best way to remove dirt?

Exposed concrete slabs do not have a uniform surface, which means they are said to have better slip resistance than other (smooth) surfaces. However, a disadvantage of this structure is that dust and dirt can settle on it more easily. As a result, unsightly deposits – such as green deposits, moss and algae – collect in all cracks, crevices or cavities. This in turn increases the risk of slipping, and dirt also spoils the beautiful appearance. If you would like to clean the exposed concrete slabs, there are several options. We have summarized what these are.

One more important note in advance: In Germany, the use of chemical weed killers on sealed surfaces is prohibited because they would contaminate the groundwater. There is a risk of fines of up to 50,000 euros.

Cleaning exposed concrete slabs: the first steps

Before you start basic cleaning, you should clean the plates with a Plastic street broom Remove coarse dirt from rice straw. However, you should avoid metal tines as they could scratch the surface. After sweeping the panels, it is advisable to water them with a garden hose or watering can and, after a short soaking period, scrub them with a brush. Ideally, this will remove even the smallest dirt particles. How you can then remove the green coating and moss from the joints is explained in the next section.

Remove green deposits from exposed concrete slabs

Aside from the fact that the green veil on the concrete slabs looks anything but pretty, the surface increases the risk of slipping. Although it does not harm the material, if it is not removed regularly, it will overgrow the entire terrace. The question arises as to whether chemical cleaning products are the best solution to the problem. Although they are not banned, they are anything but environmentally friendly. If you still don’t want to do without it, make sure in advance that it is as mild as possible Green film remover does not cause any damage to adjacent plants. Or you can resort to tried and tested home remedies such as baking soda or washing soda, which are a better alternative. You can read here how to remove the green deposits.

Remove moss from exposed concrete slabs

Moss in the joints, on the other hand, can be removed with a manual one Joint scraper or one electric joint brush remove. Alternatively, you can use a weed burner, although you should only use this method on warmer days. Otherwise there is a risk that the exposed concrete will crack or crack due to the large temperature differences. If the moss (or algae) spreads on the exposed concrete slabs, it is recommended to soda To use: Mix some powder with hot water and spread the solution on the surface. Allow the mixture to take effect for a few hours before scrubbing and removing the moss with a street broom.

Last resort: pressure washer

If the methods mentioned do not lead to the desired result, there is still one option: that high pressure cleaner. You don’t have to buy a new device as rental models are available at most hardware stores. If you are still toying with a new purchase, you can use the device regularly to clean exposed concrete slabs. However, be careful when using it, i.e. always maintain a certain safety distance (depending on the pressure, at least 30 cm) so as not to damage the material or completely wash out the joints. It is also advisable to use a splash protection tarpaulin so that surrounding surfaces or walls are not dirty by flying dirt. In this video The correct application is illustrated using an example model.

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