Your best bet is to sand the door down, and finish it with multiple coats of an exterior spar varnish that's made for boats. Spar varnish contains ingredients that block UV rays and is more flexible than standard polyurethane, so it adheres better without cracking or peeling.
Use acrylic as the exterior of your fiberglass doors because they are more resistant to ultraviolet rays from the sun. Acrylics are perfect for fiberglass doors because they are designed to withstand weathering.
Fiberglass doors have a much higher resistance to weathering than wood and steel, but exposure to sunlight can fade them, as you have discovered. Depending on the fading, you may be able to patch the stain. Before you paint or stain the surface, clean your door properly.
Fiberglass doors work well in almost any climate, even extreme cold and damp conditions. Unlike wood, fiberglass doors do not warp, crack, or rot. And unlike steel, the doors don't rust, scratch, or corrode. Fiberglass is built to last and will not require yearly re-finishing to stay in top shape.
Spar varnish, for instance, has resins that resist fading from the sun. Additionally, selecting a finish with UV blockers will protect not only the coating, but the colorants on the wood under the finish. When choosing a stain, be sure to use a pigmented stain for better sun resistance.
Apply a quality latex exterior primer to your door with a wide paint brush. Cover the front of the door as well as the sides. If your door has raised inset panels, paint these first, then paint the area surrounding the panels. For a metal door, use a primer labeled for use on metal.
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.
Do not use furniture wax. It is not designed for outdoor usage, and will bake the finish in the sun and will result in damage. Once you have your wax, applying it correctly is key. You should never wax your exterior doors in full sunlight.
While you can choose any finish, glossy paints are typically preferred for doors and trim, because they stand out and highlight these architectural features. They also tend to stand up to nicks and scrapes better than flat or eggshell paint, meaning they could last longer.
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.
The most common kinds of exterior door paint are acrylic resin or latex-based and with a semi-gloss finish. Latex-based exterior paint is the most flexible type and is quite popular. It fills in larger imperfections on a door's surface and resists cracking and chipping.
While it's often recommended to remove your front door in order to paint it, it is possible to paint it without taking it off its hinges. Paint a front door and you'll easily add instant curb appeal to your home. The front door is your welcome sign.
Wood should be pressure washed and in good condition prior to sealing or coating. For metal and plastic, apply a container of furniture protector to minimize the impact of heat and radiation. Upholstery should be cleaned with soap and water. Make sure it dries completely to avoid mildewing.
Always choose the right paint to prevent paint fading. As a homeowner, you should choose a light color with a reflective layer. That way, your walls will reflect the light and UV rays. Also, it's better for your paint's color pigment to be chemical, since organic color pigments don't resist UV light well.
That's why lighter colors last longer and fade less than dark colors. And because dark colors fade faster, they are more difficult to touch up.” Red exterior paints tend to fade the fastest based on how their specific pigments interact with UV light.
The good news is that there is an option for homeowners who must contend with a hot climate: fiberglass doors. Fiberglass is a remarkably durable material that will hold strong even after years of facing the hot sun.
If your exterior door is exposed to the elements, then a storm door may be the way to go to protect your door. If you have a new, well insulated, energy-efficient exterior door, you may not need or want a storm door. If you live in a warmer climate, a storm door may not be the best option.
Do not use car waxes that also clean or car polishes with cleaners which may contain abrasives and may damage the finish of your door. Only wash and apply protective sealant when door is cool to the touch.
Clean & Dry
Wash and scrub your exterior wood door with natural dish soap. When cleaning the door, ensure the cleaning products are diluted with water so that the cleaners themselves don't damage the wood. Then, dry the wooden door with paper towels or cloths.