What Are Composite Doors?

What Are Composite Doors?

Date Posted

30th November 2018




Composite doors have recently become the preferred option for both new builds and replacement of existing timber or uPVC doors, but what makes them a good choice for your property? In short, they are more secure, easier to maintain, and more energy efficient than almost any other option. Here we look at their construction and key features.

What Are Composite Doors Made From?

Composite doors are exactly that – composite. They are a fairly complicated ‘sandwich’ of high performance materials which all add their properties to the whole.

Cross section of a composite door

For example, a typical composite door might be made of:

  • A core of solid wood, or insulating polyurethane foam, which makes the door light and strong, yet very energy efficient.
  • A hardwood inner frame making the door very sturdy and easy to work with.
  • A sub-frame that adds not just strength but a high security, low maintenance hinge and latching system.
  • A solid GRP (glass reinforced plastic), or a highly durable uPVC ‘skin’ that can have a realistic wood grain feel and a solid coloured surface which resists damage and never needs painting.

The result of this construction is that you get a door which looks and feels like a classic hardwood door, but has all the security and energy efficiency of a uPVC door, in one (noticeably slimmer) package.

How Are Composite Doors Made?

The details depend on the exact style of door you choose, but in general it follows this pattern:

  1. The frame of the door is built first. It will typically be made of reinforced structural members which have been cut to exact specifications. Each door is made to order.
  2. Next, the hardwood or uPVC inner frame is laid down to fit the outer frame. It may also have other reinforcing materials added for extra strength at this point.
  3. The locks, hinges and latches are added, secured firmly to the solid frame.
  4. The front and rear faces are added at this point, and the door really begins to take shape. These will typically be made of durable uPVC or GRP.
  5. Depending on the door’s construction expanding polyurethane foam is injected between the faces at high pressure, to ensure that it fully penetrates the door structure. This adds not just strength but insulation, keeping the heat in on even the coldest days. Alternatively, the core can be made from solid timber.
  6. The door is then finished by hand to the finest standards. This includes cutting and fitting the windows, installing the letter box and any door furniture.
  7. After a careful quality inspection, the door is complete, and ready to be delivered.

The Benefits of owning a Composite Doors

Composite doors offer amazing performance at a very reasonable price. They are much stronger than even solid wooden doors and can withstand a huge amount of wear and tear. The outer uPVC or GRP skin doesn’t dent or crack, and it is coloured all the way through, so even if something does take a nick, there won’t be a visible discolouration.

They are also excellent at keeping the wind and rain out. The fact that the door and outer frame never warp, twist or shrink means they will stay that they have an extremely long lifespan.

Another major advantage of buying your composite door from a reputable home improvements company is their security performance. Get one that comes with a bespoke outer frame and enhanced locking system that meets British Standard PAS 24-1 standard for ‘Enhanced Security Doors’.

How Much Does a Composite Door Weigh?

Of course, that will vary depending on the size of the doorway it is made to fit and the glazing options you choose. However, they are much lighter than you would expect. A ‘typical’ composite door without heavy glass or fittings might weigh less than 30kg.

How Thick is a Composite Door?

Again, this is variable. Typically, they come in 35mm, 44mm, 48mm and 65mm thicknesses, but could be manufactured to almost any thickness you could imagine. The thicker doors are of course better insulated (there is that much more timber or polyurethane foam between the outer panels). However, the thinner doors are lighter, and are better suited to window inserts.

Composite vs. UPVC Doors vs. Timber Doors

Timber doors are of course the classic option, and the ‘standard’ by which other types of door are measured. They are strong and easy to work with. On the other hand, they have a tendency to expand and contract over time, and to shrink or swell in dry or humid conditions. They also require a fair amount of work to maintain, and need to be painted every few years.

uPVC doors were extremely popular when they first came out, and can be found in millions of homes throughout the UK today. Compared to timber doors they are lower maintenance and very long lasting. They also support more complex locking and latching technology, making them more secure. However, they rely on the strength and integrity of their inner panel and if this is not reinforced they can be relatively simple to break in through. A reputable home improvements company supplying uPVC doors will always advise on this aspect of their design.

Composite doors are a more recent development, and are becoming more popular because they combine several of the advantages of timber and uPVC doors, and few of their disadvantages. Composite doors offer excellent security, as they take advantage of the locking technology developed for their uPVC counterparts. However, they do it with a generally smaller outer frame, so they fit better into more traditional entryways. They also offer excellent insulation values and a weatherproof seal.


In conclusion, composite doors benefit from a complex, layered construction which gives them strength, durability, and the look and feel of traditional timber doors. They also come in a superb choice of different colours and styles, and can be tailored with many different hardware and glazing options to give you a completely personalised product that will look exceptional when installed in your home.

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