Maintenance coats should be re-applied about every 2-3 years or at the first sign of the stains return. This product is also effective on nearly any exterior painted or unpainted hard surface once stains have been removed.
Protection To Prevent Black Roof Stains From Returning
This milky white liquid treatment dries to a clear natural look. Simply spray on cleaned asphalt shingle roofs to form an invisible barrier that blocks the return of unsightly roof stains. Maintenance coats of Stain Blocker for Roofs can be re-applied every 2-3 years or at the first sign of stain return to help block further staining. DEFY® Stain Blocker for Roofs contains no acids, caustics, or bleaches and will not harm plants when used as directed.
DEFY® Stain Blocker is the second step in a 2 step system to clean and protect your roof. For application instructions, see the data sheet above or click here.
For a detailed report "Asphalt Roof Cleaning and Stain Prevention" click here.