Frequently Asked Questions

The market for composite doors is huge and bewildering and here we list some vital questions you must ask first before buying a composite door.

We outline the pitfalls, pros and cons of the composite door marketplace – and why The CDC composite door is different from all others.


Q – What is a composite door?
A – Any door can be called a composite door as long as it is made from 2 or 3 different materials. The CDC composite door is manufactured using a CFC free foam core with a through coloured GRP (fibreglass) skin either side. Across the market, composite doors vary in thickness from 35mm to 65mm - but thickness is only one part of the story. The CDC composite door is 44mm thick because its combination of high-performance composite materials is unique. This combination ensures exceptional insulation against noise and heat-loss.
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Q – How do different housing sectors influence the companies who make the composite doors?
A – Some companies manufacture doors for the social housing sector, others solely for new builds, and only a few manufacture for the retail customer.

1 – The social housing sector requires large volume production, perhaps 5,000 or 50,000 units. These doors will come mainly in 2 or 3 different colours and are fitted with a standard clear backing glass. They are price-driven, usually put together very quickly and often fitted with the cheapest locks and hardware.

2 – The new-build sector varies from one housebuilder to the next. Budgets will decide what standard of door will be fitted. These doors will often be faced with a steel skin – which may be OK for 5 years. But the disadvantages are that the skin is about 3mm thick and when it dents you can not smooth out the dents. The paint is sprayed on, so one day it will start to flake off – see the pictures.

3 – The retail sector tends to demand a better door so it is important to choose a company that delivers value for money. The CDC composite door is a premium product both in design and the specification of its composite materials. We believe it looks elegant and offers superior performance to rivals – please check the right-hand column for the major trade accreditations and certification standards which the CDC composite door meets, especially the benchmark ISO 9001. You won’t find many other companies being as widely endorsed as CDC.

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Q – Are all the door skin finishes the same?
A – No. There are lots of different finishes. Some leave very large gaps between the grain on the door which results in a plastic door failing to look like a timber door. The CDC composite door has a glass-fibre skin which feels exactly like the grain of wood, and its colour is an attribute of the material itself.
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Q – What’s inside most composite doors?
A – Materials vary wildly. Some doors have solid wood cores – which sounds really strong, doesn’t it? Yes, until the sun beats down and causes laminates to separate, or mouldings to crack – see pictures. The CDC composite door resists damage by the sun, and provides six times the heat insulation of wood.
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Q – How long are doors tested in real weather conditions?
A – Many companies test their doors outside for only 4-5 years and rarely in extremely hot or cold conditions. Yet they will offer you a 10 year guarantee, or sometimes longer. If a company cannot offer you proof their doors have been tested outside for the guaranteed period - be careful. Saving a few pounds now could turn out costly in the long run. The composite materials in every CDC door are tested in severe weather conditions for at least 10 years and are guaranteed accordingly.
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Q – What are resin bevals?
A – These are imitation glass lookalikes made from a plastic resin trying to imitate a traditional glass bevel. Easily distinguished from the real thing, they do not carry a high class traditional bevel finish. The CDC composite door incorporates only real, durable glass.

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Q – What is suited door furniture?
A – Many companies fit a variety of hardware to their doors and this can lead to letterplates, handles, knockers in mismatched shades of steel, chrome or brass. The CDC composite door furniture all matches, in the style of your choice.

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Q – Why is an outerframe important?
A – An outerframe is a door’s surround and it is fitted into the brickwork (which a door leaf itself then fits into). The CDC composite door outerframe is fully reinforced for exceptional security, and is fitted with three seals to ensure no penetration during bad weather.
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Q – How do door hinges differ?
A – Hinges vary greatly, often to make fitting easy. Some companies use large flag hinges which look unsightly and encourage poor workmanship. They enable doors to be fitted roughly to the vertical, and then realigned by adjusting the flag hinges – see pictures. Hinges on The CDC composite door are classified as pencil hinges (with bearings inside). The door opening is prepared to allow an accurate squared-up fit before despatch. On site, the rigid pencil hinges ensure true alignment, with an extra hinge near the top to help support the extra weight of The CDC composite door – see pictures.
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Q – What are u-values?
U-values are now required on all new-build houses to help reduce the nation’s carbon footprint. Every CDC door meets these new requirements (see table: the less glass in the door, the better the u-value). The CDC composite door gives your home the highest insulation available (which means savings on your heating bill) and high acoustic performance for noise reduction.
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Q – Why do prices vary so much from one supplier to another?
A – One reason is simply that some companies compete on price alone. In addition, as you can imagine, there are 100 ways of combining the materials that go into composite doors, and as many ways of keeping manufacturing costs down. What would you choose — a short-term fix or a long-term solution? You may pay a little more for The CDC composite door but you are buying craftmanship, durability and quality.
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Q – What styles of glass can I have if I can’t see something I like?
A – All glass designs in The CDC composite door are customised to each customer’s needs. You can have anything you wish — within reason!
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Q – What if I don’t like your five rich Victorian colours?
A – You may order The CDC composite door in any colour in the British standard range or on the RAL colour match chart. For example, greens vary from British racing green, leaf green to grass green etc. You can choose from a traditional Victorian blue to a neon blue to a sky blue. Colourwise, the sky’s your limit. Or you could stick with natural wood-grain effects in Rosewood or Golden Oak.
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Q – What makes your door skins so different?
A– Skins for The CDC composite door have been specially made by combining GRP with specialist stabilisers in order to prevent cracking and movement of the door.
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Q - What is GRP?
A – It stands for Glass Reinforced Plastic (glass-fibre), the basic material of The CDC composite door. This is a strong and highly durable strong composite used in the manufacture of modern high-speed boats.
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Q – Who fits The CDC composite door?
A – We supply companies all over the country. These tend to be reputable companies with proven track records of over 10 or 20 years. They are familiar with the high standard required for the fitting of The CDC composite door. We also offer our own fitting service throughout Yorkshire.
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Q – What guarantee do you give?
A – The CDC composite door slab itself has a 10 year guarantee not only from us but also from our supplier.
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Q – Will The CDC composite door last longer than guaranteed?
A – Every CDC door is made from a glass-fibre composite which has been weather tested for at least 10 years — and it is still going strong. Like anything in life, if you look after your new CDC door, there is no reason why it won’t last you 30 years or more. Useful tips – engaging the door handle correctly in the door frame will make for long life. Wipe the door down with only a damp cloth – do not use strong chemicals on the surface. In years to come, your CDC door will be admired by the next family to step through it.
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