Airless Sprayers for Roof Coatings

An airless sprayer is the most efficient way to apply roof coatings. Airless sprayers use a hydraulic pump to atomize the coating. Elastomeric coatings require higher pressures and flow rates than paints. A roof rig usually has a minimum pressure of 3000 psi with a flow rate of of 3 gallons per minute.

An airless sprayer pump capable of developing 1,800 to 2,500 psi material output pressure should be sufficient to spray a variety of roof coatings. A siphon hose on the material inlet typically is used to draw material directly from 5-gallon pails or 55-gallon barrels.

A spray gun with an extender wand allows for comfortable coating application without having to hold the spray gun uncomfortably close to the surface. A 517 tip is usually recommended for roof primers and 631 for elastomeric coatings. Tips are reversible for easy cleaning and clearing of occasional tip clogs.

Proper spray technique involves keeping a gun level with a roof’s surface at all times, maintaining a consistent distance between the spray tip and surface. Use a overlapping, crosshatch pattern to ensure complete coverage and a uniform finish.

Choosing the Right Airless Sprayer

Tags: Airless Sprayers, Elastomeric Coatings, Roof Coatings

Recommended Airless Sprayers

• Graco GH833 Roof Rig
• Graco GMax 7900
• Titan Hydra Series
• Titan PowrTwin Series

Don't forget Pressure Washers

A pressure washer is mandatory for preparing a roof's surface for coating application. Pressure washing removes embedded dirt, chalking and poorly adhered material. In most cases, 2000 PSI can adequately clean the surface without damaging adhered roofing laps, masonry or flashings. Higher pressure ratings can speed up cleaning provided that a wider nozzle is used to prevent damage to the existing substrate.

Clear-rinsing detergents may be used to improve cleaning. Be aware of any local restrictions regarding how the wash-off water must be treated or released into storm sewers or swales.