Do Fiberglass Doors Rot Or Rust Over Time?

The door is the focal point of your home. As much as it is a statement, it is also a valve—to ward off intruders, to keep you safe from elements, and to protect you from any unwanted harm. It is therefore important to find a door that does not rot or rust over time. We've done our research and here's what we found out.

Fiberglass doors neither rot nor rust over time. They can crack from hard impact but exposure to extremes of weather will not attack their grains to cause rotting or oxidize their material resulting in rust. The same material used to craft airplanes or surfboards is used to make your fiberglass doors.

Keep reading to understand why fiberglass is a better choice for your door. We'll also discuss its advantages and disadvantages.

Vertical shot of an emergency exit door with a fire alarm, fire extinguisher, and an emergency light hanging on the wall next to it. Do Fiberglass Doors Rot Or Rust Over Time

What is the benefit of a fiberglass door?

A fiberglass door provides you with the appeal and aesthetic of wood and the durability of a steel door with an added advantage of insulation and warranty.

Fiberglass is a fiber-reinforced plastic. It is flexible, chemically inert, stronger than metal, non-conductive, and non-magnetic. Like a steel door, it can last you well over 100 years without the risk of corrosion.

Additionally, a fiberglass door does not absorb heat or moisture, so it is not prone to warping or shrinking usually encountered with a wooden door. Because of this, manufacturers confidently provide a lifetime warranty and will replace it for free if you still own your house.

Aesthetically, the skins can now mimic wooden doors that are quite difficult to replicate if you use steel doors. Unlike wooden doors, prolonged use will not wear and tear the hinges since it is light in weight. You can open and close the door without the risk of sticking or bonding. They are also reinforced with a steel frame on the latching side which prevents unwanted or forced entry.

And since it comes with an insulating foam inside, it can ward off cold or heat coming from the outside. Mostly rated as R6 compared to wood, which is only rated R2 in terms of insulation, some brands are even recognized to be energy efficient, earning the US Government recognition as Energy Star™ Rating. However, this may diminish if you add a window despite using low emissivity glass or low-E glass.

The price generally comes between that of a wooden door and a steel door for the initial cash layout. Provided with enough protection, it proves to be more efficient because it can withstand decades of no retouching or repainting.

How durable are fiberglass doors?

exit gate or fire exits in the building Ideas for evacuation drills in the event of a fire

Fiberglass is considered one of the most durable materials in the world. Prolonged exposure to moisture will not decay or corrode your door. Molds, insects, and mildew cannot penetrate at all.

Fiberglass doors' high corrosion resistance contributes to their durability, which proves to be advantageous in a high moisture environment.

When it comes to impact resistance, fiberglass can outperform steel or metal. The strength to weight ratio of fiberglass can be up to 5 times that of wood or metal. This is possible as the components making up the fiberglass (fiber and resin) contribute equally in managing the external factors as it interacts with them. The reinforced fiber component takes care of the load while the resin distributes the weight accordingly.

Do fiberglass doors need maintenance?

Fiberglass doors are very sturdy that they require minimal maintenance. They can last for 15 to 20 years without repainting. If your door has incorporated low-E glass, expect to have a change between 10-20 years. If the door is exposed to harsh elements like extreme rain, heat, or snow, then you might expect the skin to tarnish between 1 to 2 years after being installed.

The light weight of the door also reduces the tensile pressure on the hinges, so you don’t expect to be changing them quite often.

To maintain you fiberglass doors in their optimal condition, we listed below some helpful considerations:

Add an Overhang

Installing an overhang may prevent early discoloration. If discoloration has occurred anyway, you may consider refinishing, repainting, or patching depending on the extent of fading.

Strategic Door Placement

Install your door away from harsh southern or western sun exposure. If the destined spot is in the southern or western part of the house, consider installing a light-colored door that snugly fits in the door frame.

Contemplate if You Really Need a Storm Door

While a storm door can add protection to your fiberglass door during heavy rains or storms, it can also trap heat during hot months. If necessary, choose the vented type so that heat will dissipate.

Keep Your Doors Clean

Daily cleaning helps to remove grime and dirt that can flake your door skin over time. Applying marine wax at least once a year to your fiberglass doors can also protect the skin and make them less prone to ill environmental effects.

Know Your Fiberglass Door Well

Do remember that not all fiberglass doors are created equal. There are lower-quality doors present in the market. And while the material itself promises to be exemplary, the manufacturing process and design of the door are major determinants of its performance. So, choose a door brand that delivers its promise.

What is the best brand of fiberglass entry doors?

There are several manufacturers that offer a range of fiberglass doors for your entryway including ThermaTru, Masonite, Peach Tree, Kolbe-Kolbe, Pella, and Jeld-Wen.

But according to a window and door magazine, the top manufacturers of fiberglass doors are the following:


The company started in 1962 and introduced the first fiberglass door in 1983. In the last 30 years, they have provided entry doors to thousands of homes and have products available in wood, steel or fiberglass. Their Classic Craft® line has been rated a Consumer Digest Best Buy for exceptional warranty, quality of materials and construction.


Founded in 1960, they also offer exterior doors available in wood, fiberglass, and steel. Smooth-Pro™, Architectural™, IWP® Aurora®, and Design-Pro™ are their specific brand for fiberglass doors.


ProVia is known for old world craftmanship and manufacturing of high quality entry doors. They manufacture the most energy efficient door in the US. Their Embarq Door is their fiberglass offering. It is thicker than most doors available in the market and offers a dual perimeter seal and insulation channels in the side rails and header of the door.


One of the late entrants in the fiberglass door category but Pella has been in the market since 1925. They sold their first fiberglass doors in 2000. One of their popular products, the VividGrain™ stain, gives your fiberglass door a finish that mimics real wood.

Which is better: steel or fiberglass doors?

Purpose precedes function—the choice of which is better and will depend on where you need the door installed.

Since steel doors are thicker, they serve better for security reasons. They are harder to break and almost impossible to remove. The drawback is that they are less appealing due to limited color choices and designs and higher chances of corrosion.

A fiberglass door may have more curb appeal than a steel door. You have a wide range of designs available from traditional to contemporary look. And high-quality fiberglass doors can also offer a high level of security. It may also be good to check on your neighborhood what types of doors are installed to give you a better idea. You may also want to confirm if there is a prescribed type of door design.

The state in which you live can also help you choose—fiberglass doors offer more insulation so they may prove to be beneficial if you have longer winters. They are also preferable if you live in areas near the coastal area since steel doors are more prone to corrosion.  

The overall recoup for fiberglass door approximates that of steel door based on the recent National Association of Realtor data, 74% and 75%, respectively. On average, steel doors will cost you about $2000 while you need to shell you $2700.  Despite being cheaper, steel doors require regular maintenance compared to fiberglass doors. So the difference may well be spent over time to ensure your steel doors retains its function.

In Summary

Fiberglass doors have proven not only their durability but also flexibility in design, style and function in the last 30 years since their first introduction. They are as durable as your steel door with more benefits of insulation and warranty.

You can easily open and close your fiberglass door with not much effort due to its light weight. Not only does it add curb appeal but recent data has shown that it approximates the recoup for steel door and that it can also increase your home's perceived value.

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