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What goes into a composite door?

Table of Contents

What goes into a composite door? Well, the clue is in the name!

Composite doors are made of a combination of materials, including uPVC, foam, wood and GRP, which is a glass reinforced plastic. These materials are combined in layers, each strengthening the door and helping it to outperform many other materials in terms of security, thermal efficiency and weather resistance. Let’s break it down in more detail…


uPVC is a type of plastic commonly used in the external elements of a home, such as window frames, soffits and guttering. This is because it is waterproof and weatherproof – meaning it will help protect the home from the elements while maintaining its appearance. On its own, however, uPVC isn’t particularly good at insulating – unless it is assembled in the clever chamber-like formations that we see in casement windows, but we will save that for another blog!


Foam forms the inner core of the door, creating a protective, thermally efficient barrier to heat and cold. Why? Foam is a solid material formed with small air bubbles throughout, which prevents heat energy from flowing through. Foam is also a really effective sound barrier, which is why it is used in soundproofing and helps our composite doors eliminate external noise.


Wood is used to create a traditional, aesthetically pleasing frame around the door. Timber also provides strength, and stability as well as a degree of flexibility, which means the composite door can be fitted perfectly within the entranceway.


GRP is typically used for the outer layer of a composite door. It is a type of plastic that is reinforced with glass fibres which makes it very strong and durable.

Other materials

In addition to the four primary materials listed above, some composite doors may also include other materials, such as:

  • Glass: If you choose to have glazing in your composite door.
  • Metal: For the hardware, including hinges, handles, and sometimes frames.
  • Weatherstripping: Weatherstripping helps to seal the door around the edges, preventing air and water from compromising the door’s performance.

Take a look at our range of energy efficient composite doors or contact us for a quote.