Washing

Regular washing of pre-painted and metallic-coated roofing products increases their durability by reducing attacks from airborne salts and pollutants.

Washing may be carried out with a hose and a soft bristle brush, using fresh water or a 10% solution of household detergent and water followed by a thorough rinse with clean water. Alternatively, low-pressure water blasting can be used at pressures up to 20 MPa, with the jet directed away from openings and sheet laps.

Stronger concentrations of cleaners than those recommended can damage coating surfaces, and avoid using organic solvents and abrasive cleaners. When cleaning coated surfaces, tar and similar substances may be removed with mineral turpentine, but the surfaces should then be washed thoroughly with detergent and water.

Always clean coated surfaces from top to bottom, and rinse immediately and thoroughly with fresh, clean water avoiding over-cleaning or scrubbing, which can damage painted surfaces.

Hard scrubbing of un-weathered bare AZ-coated steel cladding can remove the thin factory-applied clear acrylic film and cause differential weathering, affecting appearance.

If water runoff is used for drinking water, roof outlets must be disconnected before washing any roof or wall cladding using detergents. Care must also be taken not to contaminate waterways.