Beware Of Using Acid To Clean Natural Stone Paving

Acid-based formulations are not recommended for general cleaning of natural stone paving. And they should never be used, in any circumstances, on calcareous stones like limestone, marble, and travertine. This is because the acid reacts with the stone to create irreparable and unsightly damage. However, the following situations may warrant the use of acid natural stone paving cleaners on non-calcareous stones like granite, slate, or sandstone. * Efflorescence: to dissolve and remove white, powdery deposits caused by soluble salts. * Rust stains: to eliminate rust stains caused by metal structures and by oxidation of iron traces within the paving. * Mortar or grout residue: to dissolve and remove residue left after installation or repair work. * Mineral deposits or hard water stains: to break down and remove deposits that cause a dull or discoloured appearance.

The following can all be caused by misuse of acid-based cleaners. * Etching. Acid can react with the minerals in the stone, causing the surface to become rough and pitted. This etching can lead to an uneven appearance and texture, which can also make the stone more susceptible to staining and damage. * Discolouration. Acid cleaners can alter the colour of natural stone by reacting with the minerals in the stone, leading to undesired colour changes, fading, or uneven colouration. * Loss of shine. An issue that affects cleaning interior tiles more than exterior, etching caused by acid-based formulations can dull the polished or honed finish of natural stone, leading to a loss of shine and a less attractive appearance. * Weakening of the stone. Prolonged or repeated use of acid-based cleaners can weaken a stone's structure, making it more susceptible to cracks, chips, or other forms of damage. * Increased porosity. Acid cleaners can increase the porosity of the stone, making it more vulnerable to moisture penetration and staining, which can eventually lead to the growth of mould or mildew.

If a patio cleaning acid is appropriate, and recommended for your specific stone type, follow these guidelines to ensure safety and prevent damage: * Read and follow the manufacturer's instructions for proper dilution, application, and dwell time. * Test the cleaner on a small, inconspicuous area before applying it to the entire surface. * Wear appropriate personal protective equipment (PPE) such as gloves, eye protection, and a mask. * Ensure proper ventilation if working indoors. * Apply the cleaner evenly, avoiding pooling or over-application. * Rinse the area thoroughly with clean water after the recommended dwell time. * Dispose of waste properly. * Monitor results and reapply the cleaner if necessary, following manufacturer's guidelines and professional advice. I t’s inevitable that there will be spills and stains on your natural stone paving during the course of its life. With care, they should cause no problem and we recommend that you use a patio cleaner specially formulated for the stains you wish to remove. Post updated: March 2023