Cleaning and Maintenance Guide for Stone-Coated Metal Roof Tiles

 1. Cleaning Frequency: Adapt to the Environment, No Need for Excessive Cleaning

Stone-coated roof tiles have a dense surface with firmly bonded granules, offering natural resistance to dirt and self-cleaning properties. Therefore, their cleaning frequency is much lower than ordinary roofing materials and largely depends on environmental factors:

Environmental Conditions:

• Urban/Industrial/High-Traffic Areas: Greater exposure to dust, vehicle exhaust, and industrial fallout. A routine inspection every 2–3 years is recommended. Clean if noticeable dark stains appear or aesthetics are affected.
• Rural/Suburban/Clean Areas: Cleaner air and fewer pollutants mean cleaning may only be needed every 4–5 years or longer. Focus on seasonal runoff marks, bird droppings, or tree sap.

Types of Contaminants:

• Dust/Dirt: Usually washed away naturally by rain, with no extra cleaning required.
• Persistent Stains (bird droppings, tree sap, moss, algae, industrial residue, rust streaks): These can affect aesthetics and slowly erode protective coatings over time. Treat promptly when identified.

Climate Factors:

• Rainy Regions: Rainfall helps clean surfaces, reducing frequency.
• Dry/Arid Regions: Dust accumulates more easily and may require more frequent attention.
• Humid/Forested Areas: Moss and algae growth may occur and should be addressed early.

Core Recommendation: Avoid setting a rigid cleaning cycle. Perform visual inspections at least once a year, especially before and after the rainy season. Only clean when stains significantly impact appearance or may cause long-term damage. Over-cleaning is unnecessary and may even increase wear.

2. Pressure Washers: Safe if Used Properly

This is one of the most common concerns. The answer: quality stone-coated tiles, when cleaned correctly with a pressure washer, generally will not lose granules. However, improper use can pose risks.

Why It’s Safe:

High-quality tiles from reputable manufacturers use advanced processes (such as high-temperature sintering or strong resin bonding) to firmly attach stone granules to the galvanized steel substrate. These coatings resist normal rain and wind forces. Pressure washing at safe settings will not exceed this adhesion strength.

Risk Factors:

• Excessive pressure (exceeding approx. 150 bar / 2000 PSI) or using the nozzle too close to the surface.
• Narrow spray angles (e.g., 0° rotating nozzles) causing concentrated impact.
• Spraying vertically or against tile overlap, increasing stress on weak points.
• Poor-quality or heavily aged tiles with weakened coating.

Safe Operation Guidelines:

• Use medium-to-low pressure equipment, never industrial-grade high-pressure machines.
• Select a 25°–40° fan nozzle to spread water impact.
• Maintain a minimum 30 cm (ideally 50 cm) distance from the surface. Start further away and adjust as needed.
• Spray in the direction of tile flow (typically from ridge to eaves) at no more than a 45° angle, avoiding vertical impact.
• Test in an inconspicuous area first to confirm safety before larger cleaning.
• Keep the spray gun moving—never focus on one spot for too long.
• For moss, sap, or oil stains, apply a neutral or mildly alkaline roof cleaner first, then rinse with low-pressure water. Avoid harsh acids or strong corrosive chemicals.