Fiberglass Windows and Doors

If you are about to embark on a home-building project, you are going to be looking at all the possible materials you can use. There is a huge choice and it can be mind boggling. So before you go one step further, here are some guidelines that will help you understand why many people opt for fiberglass windows and doors.

The greater choice

We are going to help you identify the benefits of fiberglass doors and door and window frames. But before we even go there, it is a good idea for you to recognize the greater choice. In broad terms the choice incorporates wood, metal (either mild steel which isn’t very popular any more, or aluminum), plastic (including PVC and vinyl) and of course fiberglass. There are also windows that are made with a pre-cast concrete frame that you build into the structure of your house.

All these materials have their own benefits, ranging from eco-friendly factors to price. So how does fiberglass score?

The development of fiberglass as a building material

First off, be aware that building materials all have their own pros and cons. Some are more environmentally friendly than other, some are easier to work with, and some types are simply cheaper. You will also want to consider aesthetics.

Fiberglass is a material that was developed by the British company Fibreglass Ltd. during the 1940s. Known generically as glass-reinforced plastic (GRP) in the UK and fiber-reinforced plastic (FRP) in the US, it was developed for use in aircraft construction. After World War II it became a popular material for boat building. Because it is extraordinarily strong and stable, it was soon being used within many industries, including construction.

Today it is the material of choice for spas and the inner skin of hot tubs, and is used for storage tanks and molded septic tanks. It is also used for relatively lightweight roof sheeting and for both window and over-door canopies and dormer windows. It continues to gain popularity in the door and window trade in the form of window frames, door surrounds and doors.

Fiberglass is basically made from chopped glass fiber that is loosely woven to form fiberglass matting. This, in turn, is saturated with resin pre-mixed with an appropriate catalyst that makes it harden. In some applications, including the construction of irregular shaped fish ponds and for sealing some building elements, fiberglass may be applied in situ. But more often it is either molded in a factory, or pultruded through a heat die to shape and form it.

Benefits of fiberglass as a building material

The main advantages of fiberglass include its:

  • high strength
  • low maintenance
  • non-corrosiveness
  • minimal conductivity
  • energy efficiency
  • eco-friendliness

Well-engineered fiberglass windows and doors will be incredibly strong. For example, a well-made fiberglass window frame will have a sheer strength that is eight times greater than a good quality PVC or vinyl window frame.

Not only is it strong, but fiberglass is also tough, and will withstand extreme temperatures, both hot and cold. It can be easily sprayed or wiped clean.

The fact that it doesn’t expand or contract means that it won’t split or crack. If you consider the punishing treatment fiberglass boats and bridge structures face in corrosive salt water, you will realize just how non-corrosive fiberglass as a material is. It has a longer lifespan than vinyl, which expands and contracts quite radically (more than eight times more than fiberglass and three times as much as aluminum). Because it is non-corroding, it is also considerable more durable than aluminum.

Fiberglass also has superior insulating qualities because it doesn’t conduct heat or cold. It is said to be a lot less conductive than vinyl, and around 500 times less conductive than aluminum. A solid fiberglass door has about five times the insulating value of a solid wood door.

Its lack of conductivity as a material makes fiberglass energy efficient which, in turn, makes it eco-friendly and cost effective. In fact fiberglass has been heralded as the most environmentally friendly material for doors and windows that is available.

Companies that manufacture fiberglass windows and doors

There are companies all over the world that design and manufacture fiberglass doors and windows.

A fully integrated Canadian window and door manufacturer, Inline Fiberglass ( has been operating for quarter of a century. Not only do they design and produce windows and doors, but they also assemble them.  The company produces a range of ready-glazed window frames including casement, sliders, both single hung and double hung, bay/bow windows, picture windows and those that tilt and turn. Their range of doors is currently limited to sliding, patio and tilting doors, all of which are glazed. The company is a member of both the Canada Green Building Council and the U.S. Green Building Council and they manufacture according to ENERGY STAR standards. Their products are also rated by the National Fenestration Rating Council (NFRC).

The Canadian owned Cascadia Windows & Doors ( produces dual-action, outswing and awning, inswing and hopper, fixed and strip, and both vertical slider and horizontal slider windows. They also produce single and double leaf dual action, single and double leaf outswing and slider doors. All these frames are supplied with high-performance glazing and all either meet or exceed ENERGY STAR standards for their ability to save energy and meet LEED criteria. The company tests all its windows and doors to the required US and Canadian standards and is rated by ENERGY STAR and the NFRC. They have also opted to have products additionally rated for resistance to condensation.

Another Canadian company, the family-owned Toronto-based Bella Vista Windows & Doors (, also manufactures glazed products that boast superior fiberglass frames. In addition to casement, awning, fixed, single slider and single hung, double slider and double hung, and bay and bow windows, and sliding patio doors, they manufacture good-looking fiberglass entry doors. Available in a number of sizes and styles, the doors are designed to look like solid wood. There is a choice between a finish that imitates wood grain, and a finish that may be painted or stained. They also manufacture to ENERGY STAR standards.

Yet another Canadian company, Accurate Dorwin Fiberglass Windows and Doors (, boasts top ratings from both Natural Resources Canada and the US Department of Energy. Their products are also rated by ENERGY STAR and the NFRC. They produce awning, casement, single hung and double hung, bay and bow, as well as tilt and slide and picture windows. Their range of doors includes single entry, patio, garden and terrace designs which range from solid material to energy efficient glazed frames.

So you will see that windows and doors made from fiberglass are certainly worth considering when you build your home. The choice is enormous and quality generally great.



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