What is the Best Paint for an Exterior Fiberglass Door?

PPC and Sherwin-Williams want to help pros work smarter. We recently gave painters a chance to ask product and application questions on the SWPaintPros Facebook. In this article, Rick Watson, Sherwin-Williams Director of Product Information & Technical Services, answers one pro’s question about exterior doors.

What is the best paint for an exterior fiberglass door?

Before you do anything, check with the manufacturer of the door to make sure it’s paintable.

If the door is paintable and was previously coated from the factory, your first step is to make sure it is clean, dry, dull and sound.

Preparing the surface

I know you’re all experts here, however, with any surface prep I must remind you of this warning:

Warning: Removal of old paint by sanding, scraping or other means may generate dust or fumes that contain lead. Exposure to lead dust or fumes may cause brain damage or other adverse health effects, especially in children or pregnant women. Controlling exposure to lead or other hazardous substances requires the use of proper protective equipment, such as a properly fitted respirator (NIOSH approved) and proper containment and cleanup. For more information, call the National Lead Information Center at 1-800-424-LEAD (in US) or contact your local health authority.

After removing and/or taping off any hardware, I recommend that the surface be thoroughly cleaned with a good cleaner/degreaser to remove the grease and oils that normally build up over time.

A quality filler or putty should be used to patch holes or imperfections in the surface.

Priming and testing for adhesion

After cleaning and preparing the surface, apply a test sample of Extreme Bond Primer in an area that is less visible.

Allow to dry properly and test for adhesion. Because of the exceptional adhesion of this product, sanding may not be necessary for most clean, paintable surfaces.

Once you have established good bonding, you can prime the entire surface. Keep in mind that poor adhesion or surface prep short of clean, dry and dull may compromise the service length of the system used.

Selecting a topcoat

Many customers request the use of a water-based latex finish. For that reason, consider either:

These products have excellent flow and leveling characteristics for a smooth and durable finish on interior or exterior doors and trim. They also meet the most stringent VOC regulations with <50g/L VOC. Both are available in a wide range of colors.

Final note

If the door was previously coated with a latex or alkyd finish, no primer is needed. Just make sure the surface is clean, dry, dull and sound, and apply the finish coat directly.

Rick Watson, director of Product Information and Technical Services at Sherwin-Williams, answers pro painters’ most pressing questions in the Ask Your ProPartner™ column in PPC magazine.

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