Fiberglass is a frame material known for its strength, durability and performance. As a building material, fiberglass is nothing new. It’s been floating boats and adding strength to ladders for years. But, until recently, the complex profiles required for window designs have been impossible to attain with fiberglass. Innovative window manufacturers like Milgard® have solved these challenges and today you can buy fiberglass windows and patio doors designed to maintain their beauty in every season, in any climate.


Fiberglass is impervious to water, cold, heat, insects, salt air and ultraviolet rays—all the traditional enemies of windows and doors. Unlike wood, fiberglass frames won’t crack from dryness, swell, peel or warp. What’s more, because fiberglass frames are essentially glass fibers and resin, the frames expand and contract very little and at approximately the same rate as glass. This puts less stress on the seals, reduces the chance for seal failure and results in a clear, fog-free window that lasts for years and years.


Fiberglass is also popular because, just like a wood window frame, you can paint it. But there is one important difference—you don’t need to treat a fiberglass frame with toxic preservatives to prevent rot and decay, and it won’t deteriorate if the paint gets scraped off or otherwise damaged. Additionally fiberglass frames can have a wood veneer added to the interior. This gives you the best of both worlds: the durability of a fiberglass frame exterior and the warmth and beauty of a wood interior.


Generally more expensive than windows and doors made out of vinyl or aluminum, fiberglass windows and patio doors can be a better value over time. Their appearance has the look and feel of a traditional wood window, but their impervious characteristics and exceptional energy efficiency help to make fiberglass a superior material choice for windows and doors.