Fiber-Classic® Fiberglass Doors by Therma-Tru

Fiberglass Entry Doors in Popular Styles

Meet the very first fiberglass front door—the door that revolutionized an industry. Therma-Tru Fiber-Classic® doors changed how doors are made, and Therma-Tru still sets the standard for today’s fiberglass entry doors.

Therma-Tru engineers dreamed of an entry door that would not crack, split, splinter, or warp like wood. The result? Therma-Tru’s Fiber-Classic fiberglass entry door. Every door in this line is durable, stylish, economical and preferred by builders and remodelers.

  • The Oak Collection™ gives you the warm look and feel of natural oak graining for a timeless style.
  • The Mahogany Collection™ complements deeper wood tones in your home’s décor for a classic look.

Come home to the warmth and elegance of Therma-Tru Fiber-Classic entry door. Big L Windows and Doors proudly offers these strong, weather-resistant entry doors because they’re sure to provide the perfect protection for your home through cold Buffalo winters. Visit the Big L Windows and Doors showroom to see and touch the textured fiberglass “skin” on Therma-Tru entry doors and feel for yourself how much like wood they truly appear.


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Therma-Tru Fiber-Class fiberglass doors from Big L Windows and Doors are a great home improvement investment. They are strong, durable, and require little maintenance—especially compared to wood. They stand up to harsh winter weather and the change of seasons, won’t rot like wood doors or dent like steel doors might, and they give your home loads of curb appeal.

Therma-Tru’s patented AccuGrain™ technology gives Fiber-Classic doors realistic wood grains that look like high-grade wood. The best fiberglass entry doors are so good at imitating the rich look and feel of wood that you will think you are opening and closing a real oak or mahogany wood door. That is, until you have a few days of rain or humidity and you realize your door is still functioning perfectly—no swelling, no sticking.

You want your new entry door to be energy efficient, of course. Therma-Tru Fiber-Classic doors are engineered so that all components of your entry door system will work together seamlessly, forming a tight seal against drafts. Inside the door, a polyurethane foam core insulates against cold and heat. For superior energy efficiency, look for Fiber-Classic door styles that are Energy Star® qualified in all 50 states.


As for style, Fiber-Classic Mahogany Collection™ and Oak Collection™ Doors really deliver, with popular designs that fit a variety of architectural styles, in two of the most popular wood tones in America.

Using Therma-Tru’s interactive tools, you can design the perfect door for your home—the style, finish, color, hardware, decorative glass designs, sidelites and transom. There are options for every taste and price point. Express your personal style with door choices that range from Modern to Craftsman, Colonial, Victorian and European architectural aesthetics. Choose from ten Prismaguard stain color options for either the Oak or Mahogany collection. Add a coordinating door surround to cap off the look.

Therma-Tru Fiber-Classic doors also offer a myriad of glass options to let you create the right balance of privacy, light and style for your home. You can pick from seven privacy and textured glass options as well as decorative bevels and caming (previously known as “leading”). Add light control with convenient blinds-between-the-glass.

Exterior home improvements such as a new entry door are generally considered one of the top five home updates that pay off, with the return at resale averaging over 90 percent. Contact Big L Windows and Doors today about ordering a new Therma-Tru Fiber-Classic entry door for your home.