table of contents
- White spots
- Deposits
- Elimination
- Chemical stain removal
- Road salt stains
- Seal the paving stones
Cobblestones or concrete pavement can be found on many sidewalks or garage entrances. You can often see them in a simple gray, but they are also available in many other colors. Regardless of the color, the joy of the new stones is clouded by white spots, which often form shortly after laying. And many owners think that something is wrong with their concrete pavement. We have to agree with this in principle, but the white spots are usually a natural phenomenon that can be removed with simple means.
White spots
Where do the white spots come from?
As a rule, white spots on the concrete pavement do not come from “above”, but form out of the paving stones. They come from inside the stones, that is, from "below". That is why they are also called efflorescence in technical jargon. In contrast to a white stain on plaster or masonry, efflorescence on the concrete is not a matter of salts, but rather limescale deposits.
Whether and to what extent these limescale deposits occur depends on the cement that has been used for the concrete. The amount of limestone in the cement is important. Most of the limestone is bound, but there can also be an excess that is not bound. This excess is triggered by penetrating water and slowly comes to the surface. As the water evaporates over time, the white limescale remains on the floor.
Deposits
Do the white areas damage the concrete pavement?
The white deposits do not damage the concrete. However, many garden owners find them annoying because they do not look particularly pretty on the paving stones. They usually appear on young cobblestones that are no more than five years old. In addition, the paving stones must be regularly wet so that the excess lime can be dissolved. This is why they usually no longer occur with older concrete pavers, since after a few years all of the excess limestone has been loosened from the paving stones.
Tip: As natural deposits, the white areas also disappear on their own after a long time, as they are washed away by the rain.
Elimination
Removing white spots
The efflorescence can be removed with water or with the help of chemical agents.
Removal of stains with water
This form of stain removal is the best for nature and the environment, as only water is used in this case. In addition to the water, you will also need a brush for scrubbing.
To remove, do the following:
- Apply water
- Scrub until all efflorescence is removed
- Rinse the paving stones thoroughly with water
Tip: A warm, overcast day is ideal for removing the white deposits.
A high-pressure cleaner is only partially suitable for removing stains, as it expands the pores of the stones, which promotes dirt and corrosion. Therefore, it is better to use a brush and mop, even if this involves increased physical exertion.
Chemical stain removal
The removal of efflorescence using chemicals is controversial in the professional world, especially when it comes to acidic cleaning agents, as these agents attack the stones. In the case of colored stones, there may also be color changes on the surface. However, if you should use such a product, the concrete must be soaked well before treatment. In addition, cleaning should be carried out quickly so that the acid cannot penetrate deeper into the concrete. After cleaning, the concrete pavement must be rinsed off thoroughly with water. It is best to carry out chemical stain removal on an overcast and windless day with a temperature between 10 and 20 degrees Celsius.
Tip: When buying the cleaning agent, make sure that it is suitable for your paving stones and follow the instructions exactly. You should also test the agent on a small area.
Road salt stains
White spots from the road salt
Often white spots appear on the concrete pavement after long and cold winters. These could be caused by road salt, even if you haven't used road salt in the garden, as it is also spread on the stones through the soles of shoes. These unsightly stains disappear over time, but like the limescale deposits, they can also be removed with water.
Seal the paving stones
Seal and impregnate paving stones
Sealing or impregnation of paving stones is not absolutely necessary. However, it protects the stones from fading and also makes them shinier. In addition to these optical embellishments, the stones are also protected from other influences.
These include:
- Weather conditions
- frost
- Foreign matter
- Road salt
- Moss, algae and lichens
Seals and impregnations for concrete blocks are special products based on epoxy resin or dispersion. In order for the protection to work, it must be ensured that the joints are also sealed. You can get a suitable sealant for concrete pavement from specialist retailers. It is important that the agent does not completely seal off the soil, as this can promote frost damage. Therefore, the paving stones must remain open to diffusion, i.e. that water must be able to rise despite the protection.
Before starting the sealing, the paving stones must be cleaned thoroughly. In the best case scenario, they should look like new. After that, they have to dry off well. Only then can the sealing process begin.
Tip: Always test the sealant on a small area before treatment.
Although the sealing protects the paving stones from the weather and dirt, the stones still have to be cleaned regularly. To ensure that the stones have a long service life, they should be cleaned thoroughly once a year.
