Cleaning paving
stones
To remove dirt in the form of dust that penetrates the material’s crevices and lichen covering the stones in shaded and damp areas, it is best to use a pressure washer with a special attachment. For a lasting effect, it is also recommended to use chemical agents to destroy green growth, which simultaneously delay its return and restore the pavers’ anti-slip properties. Scraping off moss and lichen is not recommended, as this may damage the structure of the material.
Removing
stains from paving
stones
Grease or engine oil stains that have penetrated the material should be removed using specialist cleaning products for paving slabs and pavers. Their selection should be carefully considered and discussed with a professional, as agents that are too strong may cause discolouration of the surface being cleaned.
Impregnation of paving
stones
This is particularly recommended in areas prone to heavy soiling, such as barbecue areas, driveways and parking spaces. It involves coating the pavers with a protective agent that prevents them from absorbing water and liquid contaminants (oil, petrol, etc.). Impregnation has a positive effect on the material’s durability and increases its resistance to scratches and abrasion.
Weed control in joints
Removing weeds growing in the joints between pavers is no easy task. It is not recommended to do this mechanically (by pulling out the plants). It is far easier and does not damage the garden path structure to remove weeds using weedkillers, which are applied with a sprayer or a suitable marker pen.
Filling gaps
When the spaces between the pavers are filled with sand, it is necessary to top it up. The wind blowing away the sand and insects carrying it off can weaken the stability of the pavers. Therefore, the surface should be topped up with fine sand from time to time.
Efflorescence on concrete paving
blocks
The appearance of white efflorescence on precast concrete elements is normal and does not constitute grounds for a complaint. Calcium hydroxide, which forms during the standard setting and hardening of concrete, has a direct influence on the formation of efflorescence. Part of this calcium compound, which is not permanently bound to the other components of the concrete, is released to the surface as a result of water evaporation, forming a white efflorescence – calcium carbonate – on the surface of the paving blocks.
Under the influence of atmospheric conditions, mainly carbon dioxide in the air, calcium carbonate – initially insoluble in water – gradually transforms into water-soluble calcium bicarbonate. As a result of this reaction and due to rainfall, the efflorescence is washed away and disappears after a certain period of time. Repeated tests and observations have shown that this process can take between 1 and 2 years. To remove efflorescence quickly, scrub the surface of the pavers with diluted hydrochloric acid (1 part acid to 5 parts water). The surface of the pavers will become rougher, and the colour tone will change slightly. After cleaning, the pavers should be thoroughly rinsed with water.
