Glass-reinforced plastic is also known as fibreglass polymer. It’s a composite material made up of a polymer matrix that is strengthened with fibres of glass. The matrix itself is made of a thermosetting plastic, usually either polyester, epoxy or vinyl ester. It’s all reinforced with glass fibres that provide strength and rigidity.  The following is what you can expect from the material:  Strength – Compared to its weight, GRP has a lot of strength within its material, meaning that GRP is very suitable for a lot of construction projects.  Impressive Resistance Qualities – Composite doors owe GRP to its high resistance to corrosion and chemical damage, meaning that this is the material that you can thank for your protection against the harsh Scotland weather. This resistance is also what allows it to resist the effects of the outside, meaning there’s no fading or wearing of appearance. On top of the, its stability stops the door from warping or twisting from temperature change.  Design Flexibility – The ease of use that comes from this material allows us to shape the door in many different ways, which is what we owe a lot of our more premium styles to the material. It also is able to mimic hardwood, broadening the aesthetic possibilities of the door.  The GRP is the outermost layer of the door, with the solid-core UPVC within.