Natural stone requires a much more careful approach than concrete or block paving. Here's what professionals know that you might not.
Natural stone patios -- whether Indian sandstone, Yorkstone, slate, limestone, or granite -- are beautiful surfaces that command a premium price. They also require considerably more care than synthetic surfaces when it comes to cleaning. Many a natural stone patio has been permanently damaged by well-intentioned but overly aggressive pressure washing.
Why Natural Stone Needs Specialist Care
Natural stone is a product of millions of years of geological processes, and no two pieces are identical. This natural variability means that natural stone can respond very differently to cleaning chemicals and pressure washing, depending on its specific mineral composition, density, and porosity.
Sandstone -- including Indian sandstone -- is relatively soft and can be eroded by high-pressure washing, which physically removes the surface material. Limestone is chemically sensitive and can be damaged by acidic cleaning products. Slate can delaminate if water gets behind the layers under pressure.
The Right Pressure Settings
For most natural stone surfaces, we use pressures between 80 and 120 bar -- significantly lower than we'd use for concrete or block paving. The distance between the lance and the surface is also carefully controlled, and we use fan nozzles rather than pinpoint jets to avoid concentrated damage.
The rotary surface cleaners that work so well on block paving and concrete are generally not suitable for soft natural stone, as they can cause visible circular damage patterns on the surface.
Cleaning Products
Only pH-neutral, stone-safe cleaning products should be used on natural stone. Acidic products (including many common household cleaners) will cause chemical etching on limestone and marble. Highly alkaline products can affect the colour and surface texture of sandstone. Bleach-based products can cause permanent bleaching and discolouration on most natural stones.
The Importance of Professional Assessment
Before cleaning any natural stone surface for the first time, a professional should assess the stone type, its condition, and the most appropriate cleaning method. A test area in an inconspicuous location is always advisable before treating the whole surface.
If you have a natural stone patio that needs cleaning, please contact us for a professional assessment. We have extensive experience with all types of natural stone and will treat your patio with the care it deserves.
Written by the Tamworth Brighter Drives team
With over 10 years of experience cleaning and restoring driveways and patios across Tamworth and the Midlands, our team shares practical knowledge drawn from thousands of real jobs.
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