How Long Do Fiberglass Doors Last?

Made from fiber-reinforced polymer, fiberglass doors possess great tolerance against various elements. That’s why they tend to last longer than wooden doors. But how long exactly? We reached out to some manufacturers to find out the answer. 

A fiberglass door can last for around 15 to 20 years, with some manufacturers offering warranties that stay effective for as long as you have complete ownership of your home. Fiberglass doors are much sturdier than their wood counterpart, which easily equates to higher resilience and durability. Thus, it's less likely to shrink, split, crack or warp even in the most extreme heat or cold natural environments. 

A fiberglass door should be on top of your options when looking for a durable door. It's better at ensuring your safety and peace of mind. Choosing a fiberglass door has nearly countless advantages. Keep reading as we explore what those are at the same time as answering some of the most commonly asked questions about fiberglass doors. 

A rustic and earthy inspired living room with wooden flooring, wooden stairs, and a fiberglass front door, How Long Do Fiberglass Doors Last?

How good are fiberglass exterior doors?

Premium fiberglass doors are made of the same glass-fiber-reinforced polymers used in airplanes. Thus, their durability, making them last as long as 15 to 20 years, far surpasses any other wood doors in the market, whether be it oak or mahogany. This is why fiberglass doors are continuously becoming more popular among homeowners. 

There are many more reasons why fiberglass exterior doors are a good addition to your home. But we will focus on the top benefits homeowners love about fiberglass doors:

1. Durability and Versatility

The durability of fiberglass guarantees homeowners that it will not rot, warp, crack, or even corrode easily, making up for almost half the reasons why it keeps on attracting customers. And unlike wood doors, fiberglass exterior doors do not require annual refinishing. 

2. High level of security

With durability comes security. A properly installed fiberglass door provides greater security than wood doors. It's made of premium polymer that possesses superior resistance against external force, unlike wood that can easily be breached by criminals. 

3. Efficient energy usage and insulation

Fiberglass doors are created with a polyurethane foam core that is useful in conserving energy. How? This particular foam core regulates the ambient temperature well to provide just the right amount of warmth or cold in every season. 

The Department of Energy even provides a high R-value, which is a way of measuring the effectiveness in resisting extreme temperatures, to fiberglass doors. This only means that fiberglass doors can help homeowners save on energy bills. 

4. Very long warranty

Lastly, fiberglass door manufacturers offer very long warranty programs because of the inherent resilience of the product. This benefit makes a lot of homeowners upgrade from wood doors to fiberglass doors. 

Do fiberglass doors fade?

Take note, though, that their high resistance to various elements does not mean they are safe against everything. In fact, fiberglass doors still do fade with continuous exposure to direct sunlight, just like most objects. And over time, the artificial wood-colored coat can appear dull and patchy if left unattended. This is one feature that fiberglass doors share with wooden ones. 

While using overhangs can slow down the fading process, it does not stop the fiberglass from blotching. You can only rely on some maintenance practices to treat your sun-faded fiberglass doors. 

How to liven up faded fiberglass doors

According to the Door Design Lab, which sells high-quality European-themed doors, there are at least four steps to bring back the glorious shine of your fiberglass doors. These steps include cleaning, using acrylic, patching, and refinishing. Read more about the steps below: 


The fiberglass retouch process starts with cleaning the door thoroughly. Prepare a bucket of water and mix it with a non-foaming and non-abrasive cleaning detergent. Soak a sponge on the cleaning solution and start cleaning. 

The cleaning process is probably the most essential part of your fiberglass retouch process. This helps ensure that you remove loose dirt and dust that have hardened on the surface over time. This will pave the way for easier completion of the next methods you will use to liven up your fiberglass again.

Using Acrylic Paint

When trying to treat a dreary fiberglass door, an International Maritime Organization-approved (IMO) and 100% acrylic should be your top option to use in painting the fiberglass. This type of paint is specially designed for the outdoors, making it the perfect choice to coat fiberglass doors for added protection. Acrylic paint helps in making fiberglass doors highly resistant to the effects of ultraviolet rays and season changes. 

To apply, prime the fiberglass first with an exterior acrylic primer using a roller. Applying primer over the fiberglass door before painting helps in sealing the natural surface of the door. In addition, it will also fill in cracks and scratches for smoother outcomes. 

Once the primer is completely dried, use a natural bristled paintbrush to paint the door. If you’re wondering what color of acrylic paint to use on the fiberglass, we suggest that you go for light tones to bounce off light and heat from the fiberglass, which can prevent warping. Why not use dark colors? Well, they absorb more heat, which can render your fiberglass retouch and protection efforts useless. 


If your fiberglass door only has subtle faded areas, you can consider using the gel stain patch method. 

For those unfamiliar with gel stain, it is a thick stain that provides you with a wood-like finish on surfaces. It is like paint but not quite like it. Unlike paints, gel stains have a thick consistency, which makes them a better choice for patching select faded areas of fiberglass. Plus, it does not need you to remove the existing fiberglass door finish. 

To apply, select a gel stain that closely matches the color of your door. Then, simply use a small natural bristled paintbrush to paint the faded areas. Because it may appear differently after drying, apply 3 to 4 coats or until you match the existing door color. Remember to wait 24 hours before reapplying additional coat. 


Noticeable and excessive fading of fiberglass doors calls for a more drastic method—refinishing. To start this process, strip away the existing finish using steel or copper wool. Afterward, sand the door with coarse, medium, then fine sandpaper. 

Once the dust has been wiped off, start priming or staining the fiberglass door using a natural bristled paintbrush. If you choose to prime the door, use an oil-based primer, then proceed to painting the door two times, using a single stroke in both instances.  

If you decide to go with staining, follow the gel staining steps above. Right after that, coat the door with spar lacquer 3 to 4 times for that extra shine to reinforce the door's resilience against the sun and other elements.

How do you protect a fiberglass door from the sun?

Whether your fiberglass door is new or refinished, you have to put in the effort to slow down fading and prevent warping due to the continuous exposure to the heat of the sun. 

You can do so by applying marine wax to the fiberglass once a year. This will serve as your door's sun protection formula (SPF) to prevent “aging.” In addition, consider adding overhangs on your fiberglass door for that extra UV protection. 

Can dogs scratch fiberglass doors?

Although fiberglass doors are resilient to elements, the same can’t be said with deliberate actions from your dogs. Repetitive scratches from your canine companion can cause the fiber to show gouges. Fortunately, it won’t be as noticeable compared to wood doors.

You can prevent your fiberglass doors from getting damaged by attaching a steel plate where your dog usually puts his paws to open the door. 

Are Therma Tru doors worth the money?

We have now answered the most important questions for you. Now, let’s look at one of the top fiberglass doors manufacturers in the market: the Therma Tru Fiberglass Entryways. 

With its long history starting in 1962, Therma Tru carries almost 60 years of expertise in fiberglass door manufacturing. This made them become America’s leading manufacturer of fiberglass doors, as well as a company of choice among building professionals. 

True to these statements, their Therma Tru doors have always been continuously receiving praise from its consumers over the years. Who wouldn’t when Therma Tru doors are truly worth the money with the privacy, security, and energy efficiency features enabled by its “entry system.”

Final Thoughts

A fiberglass door is more than just a door; its security, versatility, and security combine in one item. With its long lifespan, you can be sure to have a fully functioning door that will protect you from the cold, heat, and elements, even in 20 years. 

Leave a Reply

Your email address will not be published. Required fields are marked *