Polyglass Roof Coatings Prep: Cleaning & Pressure Washing

When installing any roofing system, thorough preparation is the key to a successful coating application. Roofs must be clean, dry, and structurally sound to help materials such as membranes, cement, and mastic adhere properly to the roof deck. Starting from a clean, debris-free roof gives you a good foundation to work from.

There are various steps to correctly cleaning a roof. Follow our detailed guide to cleaning and pressure washing a roof to prepare it for installing Polyglass membranes and coatings.

How to clean and pressure wash the roof

Step One: Repair any damaged areas with appropriate roofing material and professional techniques. If you need to call in an external contractor, do so to get the best results.

Step Two: Remove any large pieces of debris, trash, or soil buildup from the roof before cleaning. Heavily soiled areas require pre-treatment with cleaner and physical agitation with a broom or brush.

Step Three: Use a pressure washer capable of 2500 to 3500 PSI and a 30-degree cleaning tip. Hold the spray wand 18 to 24 inches above the roof surface. With a sweeping motion, pressure wash all roof surfaces that will be coated. Take care not to direct the pressure washer under seams, or into voids or repairs in the roof surface.

Step Four: Push wash water towards drains or other outlets using a stiff broom and allow surfaces to dry.

Step Five: Physically inspect the surface to confirm that it is clean and free of any residue.

Step Six: In some situations, additional pressure washing may be required depending on the roof’s condition. Allow roof surfaces to dry completely prior to applying any coating system products.

For more information on proper Polyglass roof coatings installation, contact your Polyglass technical services rep preventative.