Typically, two coats should suffice but you may prefer to use more. Drying times vary depending on a range of factors, including: the quality and type of paint or varnish you use; the environment you are painting in and the surface you are painting.
Use acrylic, polyester, polyurethane, or epoxy resin paint on your fiberglass door. Try to pick a paint that matches the type of fiberglass for the best results. Do not use oil-based paints because these can damage the door. Fiberglass-friendly paints are often available in matte, neutral, and gloss finishes.
Fiberglass doors and sidelights can be smooth or textured with a wood-grain finish. This material usually does not need to be primed, but painting is required. Premium steel doors are factory-primed and should be painted but not stained.
Just as with the primer, let each side of the door dry before turning it over to work on the other side. Add at least two coats of paint to the door, using three or more if you want to increase the color saturation.
For a single exterior door that has been primed you'll need approximately one quart of paint.
Acrylic Latex
Acrylic paint adheres well to fiberglass, overcoming one of the main challenges to painting this material. Acrylic paint is less likely to crack and blister, and will hold up well to cleaning. This water-based paint is easy to apply, and contains fewer chemicals, so is more environmentally friendly.
Painting a fiberglass entry door is much like painting a wood door, without a need for sanding before paint is applied. Rinse the door by wiping it down with a damp sponge, then allow the door to dry completely.
Use Acetone to Clean Your Door
Before painting your fiberglass door, you need to ensure that it is clean. You may use acetone or paint thinner as the first step when cleaning. In most instances, these options are used when dealing with rather stubborn stains such as oil.
Unlike wood, fiberglass surfaces are nonporous, making them unsuitable for spray paint adhesion. Before you can spray paint any type of fiberglass surface, you will need to employ specific preparation techniques to condition the fiberglass to accept paint, or the finish will peel soon after application.
One gallon (3.8 liters) of paint can cover about 350 sq. ft (32.5 m2). Since the average doors count as approximately 20 sq. ft (1.85 m2), you should divide the surface you want to paint with 350.
Glossy or semi-gloss paints are typically used for front doors, but an eggshell or flat finish are also available. When considering flat paint, remember that it is harder to clean and will show scrapes and nicks better than a glossy paint.
Note: Don't paint the top or bottom of a door (the narrow parts that aren't visible when the door is closed). Leave them unpainted so the door can expand and contract with changes in humidity.
Rust-Oleum® Marine Coatings Wood & Fiberglass Primer primes bare, lightly rusted and previously painted surfaces. Apply to wood or fiberglass surfaces above the waterline.
A fiberglass-friendly paint can be matte, neutral, or gloss.
Due to their nonporous nature, fiberglass surfaces are not suitable for spray paint adhesion, unlike wood surfaces.
“Painting a front door is best done with a brush. This is because most front doors have wood and/or glass panels and a roller would not be able to paint in the panels the same way that a brush would to give full coverage.”
Go for a semi-gloss finish, which is as durable as it is attractive. Exterior paints are sold in flat/matte, eggshell, satin, semi-gloss, and gloss sheens, in order of the lowest to the highest luster. Semi-gloss is ideal for front doors, as it's more wear- and stain-resistant than flatter sheens.
Lay down a drop cloth to protect the ground and floor. Paint the door with an exterior-grade paint-and-primer-in-one. Leave the door slightly open as you paint to make sure you paint all the edges. Follow the manufacturer's instructions for dry time.
Painting on both sides of your front door is not necessary. You can leave the sides of the door unpainted to keep the natural texture and features. If you want to paint your front door, match the door with the colors of your exterior and interior walls.