Do you need to know how to paint fiberglass doors?
Should you paint fiberglass doors? Painting is required by Masonite for all exterior doors. To obtain your warranty, the door must be sealed with a special paint for fiberglass. All prehung exterior doors with smooth texture come primed in white ready for painting. Overtime, the primer can yellow due to sun exposure. Painting ensures the door slab is properly sealed and weather proof. Karoly’s favorite brand of residential exterior doors is Masonite by Florida Made Doors. They offer custom exterior doors near Pinellas County.

Step By Step Guide to Painting Fiberglass Masonite Doors
Please read and understand the entire painting procedure before attempting to finish the door. Be sure to follow the paint and top-coat manufacturers detailed application instructions on the product label. These instructions to paint fiber glass doors apply to the following Masonite products: Belleville® Smooth, VistaGrande Smooth, and Heritage Smooth.
Note: Painting exterior doors instructions specifically refer to the door and sidelight panels. Oil-based paint should not be used on wood frame components (frames & brickmould).
Optimal Conditions for Painting Doors
Find a well-lit painting location that is dust-free, well-ventilated and within the climate conditions recommended by the coating manufacturer. Recommended temperature should be between 50°F-90°F (10°C-32°C).
Material Needed to Paint Fiberglass Doors
What kind of paint do I need to paint fiberglass doors?
- High-quality, oil-base or 100% acrylicwater-based latex paint
of desired color - Do not use lacquer paints
- Semi-transparent stains are not recommended
PRECAUTIONS AND SAFETY BEFORE STARTING THE FINISHING:
- Never mix cleaners or solvents. This may be dangerous as well as ineffective.
- If using commercial cleaning or finishing products or solvents, carefully read
and follow safety instructions, warnings, cautions and disposal instructions on
manufacturer’s labels. Wear appropriate safety gear (e.g. clothing, goggles, gloves)
and provide plenty of ventilation. - Immediately clean spills.
- Most solvents are flammable and/or toxic and must be handled with extreme care. Do not use near open flame, sparks, or electrical motors.
Coatings & Accessories
- Mineral spirits or acetone
- One pair of rubber gloves
- Mild detergent in warm water
- Stir sticks
- Masking tape
- Safety razor blades
- 200 grit sandpaper
- 2-1/2″ wide brush appropriate for type of paint (a natural bristle brush should be used with oil-based paint and a synthetic bristle brush should be used with latex paint.)
Tools
- Hammer
- Pin punch
- Safety Glasses
- Phillips screwdriver
- Pliers
- Air-less sprayer (optional)
Step 1 – How to Start
You can paint fiberglass doors either by hanging in the opening or removing it from the frame (recommended). Take care to protect it from damage should you remove the door. Sidelights will need to be finished vertically. Use a pin punch and hammer to remove the door from the frame. Then, strike the hinge pin from the bottom until it pops up (for outswing units – hinge leaf must be removed from the door). Drive the hinge pin as far as possible with the punch. Next, grasp the hinge pin using a pair of pliers, and, while twisting, pull the pin out. Finally, remove all door hardware.
Step 2 – Preparing the Fiberglass Door Surface
IMPORTANT: For adequate paint adhesion, the door surface must be free of dust, debris and other surface contaminants.
When painting exterior doors, the fiberglass should be wiped clean with a solvent such as mineral spirits or acetone. Now, allow the cleaning solvent to dry completely – until there is no residual odor. Next, the door must be washed with a mild detergent in warm soapy water, rinsed and then dried. Finally, mask (tape) off all surfaces that will not be painted, including all glass.
Step 3 – Painting the Door Surface
Use exterior, high quality, oil-based or 100% acrylic water-based latex paint of desired color. High quality interior paint can be used on the interior surface of the door only. Lacquer paints are not recommended. Follow the manufacturer’s instructions for paint application by using either a brush or a handheld sprayer.
Put on gloves, safety glasses and prepare your materials. Before starting, and occasionally throughout the project, stir the paint using smooth strokes until the texture is creamy – avoid creating bubbles.
Finishing Order:
- Panels and sticking (moulding profiles)
- Vertical center areas (mullions)
- Horizontal areas (rails)
- Outside vertical areas (stiles)
- Edge of door or stiles


Finishing with Brush Application
Dip the brush into the paint. Then use the rim of the container to release any excess paint. Apply paint as evenly as possible while still wet.
Brush strokes should follow the grain direction of the selected area. First, start working on the panels and sticking (moulding profiles). Second, move to the vertical center mullion. Third, paint the horizontal rails. Then, do the vertical stiles. Finally, the outside edges (stiles and top rail, see figure 1 for details). Doors that are outswing or have adjustable surface mounted sweeps will need to have the sweep removed and the bottom rail painted.

Finishing with Brush Application
First, follow the manufacturer’s instructions for thinning the paint; (i.e. thin latex paint with water or oil-based with solvent for better atomization and spraying results). Then, strain the paint before filling the spray pot.
The door can be painted in horizontal (recommended) or vertical position. However, the paint should be applied in continuous strokes extending six inches past the edges of the door. This will ensure uniformity across the entire surface of the door. In that case, multiple light coats are better than one heavy coat.
Avoid runs as a result of over-spraying.
Drying Your Exterior Door
IMPORTANT: Let the paint dry completely, following the manufacturer’s recommended drying time before handling the painted surface or applying a second coat. Scuff sanding or light sanding may be needed in between the coats based on manufacturers recommendation. Do not sand the final topcoat. If possible, allow the door to dry in a horizontal position to minimize paint runs. High humidity and/or low temperatures may extend your drying time.
WARNING: Doors painted with dark colors or doors with attached non-vented storm doors may become very hot to the touch in direct sunlight and may void the warranty.
DO NOT paint the weather strip and do not close door until paint is dry (see paint manufacturer’s specifications on minimum drying time).
To maintain product warranty: Paint the door, frame, header and brickmould within 45 days of installation. Repainting every 1 to 7 years will be required, depending upon weather exposure.
DO NOT use glass cleaning products (such as Windex), acetone, gasoline, benzene, lacquer thinner, chlorinated solvents, gritty abrasive scouring compounds, or alkaline cleaners to clean the acrylic inserts as damage to the insert will occur.
DO NOT use squeegee, scraper, or synthetic rags that may scratch.
NEVER scrub the acrylic. Gently wipe surface with a soft, scratch-free cloth.
Do your have more questions?
Submit your questions, along with your name, email and phone number, using the following form and a representative will contact you within 2 business days.