External Doors Buying Guide: Choosing a Front or Back Door

Choosing the right external doors means balancing security, weather resistance, appearance, glazing, size and maintenance. A front or back door is exposed to far more demanding conditions than an internal door, so the exact product specification matters as much as the style. Whether you are planning a front door replacement, fitting an extension or completing a new build, measuring correctly and understanding the material options will make the buying process much easier.

This UK external doors buying guide covers uPVC and wooden front doors, common sizes, measuring, glazing, colours, handing, frames, hardware and fitting checks. It also links to real JJ Building Materials products and our more detailed guides so you can research each decision without relying on generic one-size-fits-all advice.

What should you check before buying an external door?

Start by confirming whether you need a door leaf only or a complete door-and-frame product. Then check the overall dimensions, opening direction and handing, frame or cill details, glazing, colour inside and outside, supplied hardware and any stated performance information. The product description should be the source of truth because external-door packages vary significantly.

If you are replacing an existing front door, photograph the current opening from inside and outside and record the width and height in several places. If you are changing the frame as well, the measurement you need may differ from a simple leaf replacement. Our how to measure for an external door guide explains the survey process in detail.

uPVC front doors: practical and low maintenance

uPVC front doors are popular because they are supplied as practical exterior-door systems with factory-finished frames, glazing and hardware configurations. They generally require less routine finishing than unfinished timber, which can make them attractive for replacement projects where you want a straightforward, consistent appearance.

JJ Building Materials stocks Crystal uPVC doors in multiple glazing and colour combinations. For example, the Crystal UPVC White Triple Glazed Single Door Full Glass LH Clear provides a highly glazed white option, while grey-and-white products such as the Crystal UPVC Grey 7016 / White Triple Glazed Single Door Full Glass LH Clear offer a different exterior look. Always check the exact size, handing, glass and contents on the product page.

Wooden front doors: character and finish flexibility

Wooden front doors can suit traditional, contemporary and renovation projects where natural material and finish are important. Timber external doors may be supplied unfinished or with a specific treatment state, and that affects what needs to happen before or after installation. Manufacturer guidance for sealing, finishing and protecting all required edges should be followed carefully.

The main advantage of timber is design flexibility and natural character, but it also demands more attention to finishing and maintenance than a factory-finished uPVC system. Check the exact construction, glazing, trimming allowance and weather-protection instructions rather than assuming all wooden doors behave the same way.

uPVC vs wooden front doors

The best choice depends on your priorities. uPVC is usually appealing when low maintenance, factory-finished appearance and a complete modern door system are priorities. Timber suits buyers who want a natural material, traditional detailing or the ability to use a chosen paint or stain system where the product permits it.

Our dedicated uPVC vs wooden front doors guide compares the two options across maintenance, appearance, measuring, glazing and project suitability without pretending there is one winner for every home.

External door sizes in the UK

Traditional UK external door leaves are available in several commonly stocked sizes, including imperial-derived dimensions such as 1981mm heights with widths including 762mm and 838mm. Complete uPVC door systems often use their own frame dimensions, so you should never assume a standard timber leaf size applies to a factory-made uPVC doorset.

Our external door sizes UK guide explains the difference between front door leaf size, frame size and structural opening. Whatever size family you are working with, measure the actual property and compare with the exact product dimensions.

How to measure for a front door replacement

Measure the width of the relevant opening at the top, middle and bottom and the height at the left, centre and right. Note whether your measurement is the structural opening, the outside of an existing frame or a door leaf. Check the threshold and finished floor, and measure diagonals where useful to identify a badly out-of-square opening.

If the product includes a frame and cill, use the manufacturer or supplier's measuring guidance for that exact doorset. Do not subtract a guessed allowance from the opening and order on that basis. A competent installer can confirm the required fitting tolerance before purchase.

Clear, obscure and decorative glazing

External-door glazing changes privacy, daylight and appearance. Clear glass is useful when natural light and views are priorities, while obscure glazing can provide more privacy in a front entrance. Some doors use full-height glazing and others use half panels or smaller inserts.

Real Crystal products in our range include clear and obscure options such as the Crystal UPVC White Triple Glazed Single Door Full Glass LH Obscure. Check whether glazing is double or triple, clear or obscure, and whether those characteristics are fixed for the product or selectable by variant.

Front door colours and inside/outside finishes

Colour can transform the exterior of a property, but product titles sometimes distinguish between exterior and interior frame colours. A grey 7016 exterior with a white interior is not the same as grey on both sides. Read the full title and variant details so the inside appearance does not come as a surprise.

White remains easy to coordinate with many window and fascia schemes, while anthracite-style grey works well with contemporary exteriors. If visual matching to existing windows matters, compare the stated colour reference and physical samples where possible because materials and manufacturers can have slight differences.

Left-hand and right-hand external doors

Handing describes how the door is configured to open, but terminology can be confusing because suppliers can describe it from different viewing positions. Never infer handing from the letters LH or RH without reading the product's own explanation or diagram. Check which side carries the hinges, which side carries the handle and whether the door opens inward or outward.

Several Crystal products explicitly include LH or RH in their titles. Use that as a prompt to verify the configuration rather than as a reason to assume. An incorrect handing choice can make an otherwise correct-size door unsuitable for the entrance.

Security and locking

Security is a major external-door consideration, but avoid judging a complete door purely by a single marketing phrase. Check the exact locking system, cylinder or hardware included, glazing specification, frame construction and any stated security certification for the product. If a project needs a specific standard, verify it on the individual listing or manufacturer documentation before ordering.

Also consider day-to-day use: where the letter plate, handle, thumbturn or key cylinder sits, whether the door is a main entrance or secondary access point, and how the hardware will be used by the household.

Weather resistance and thermal performance

A front door should be designed for external exposure, but exact weather and thermal performance differs by product. Look for stated U-values, glazing information, threshold details or performance declarations where supplied rather than assuming all uPVC or timber doors perform identically.

Good installation is also crucial. A well-specified door can still perform poorly if the frame is not level, perimeter gaps are not sealed correctly or the threshold is unsuitable. Product performance and installation quality work together.

Do you need a new frame?

If you are replacing a timber door leaf and the existing frame is straight, sound and appropriate for the new leaf, it may be possible to retain it. If the frame is rotten, distorted, insecure or wrong for the new thickness, replacement can be the better route. uPVC replacement doors are commonly supplied as complete framed systems, so read the package details carefully.

Changing a frame can affect the structural opening, internal plaster or trims, external sealant and threshold. Include that work in the project plan rather than treating it as a small accessory decision.

External door hardware checklist

A complete doorset may include much of its required hardware, while a door leaf may need hinges, lock, handles, cylinder, keeps and other components sourced separately. Check the contents before adding duplicate items. For general hardware, explore our door accessories and door handles.

External hardware should be suitable for the door, exposure and security requirement. If the manufacturer specifies particular components, use compatible products rather than choosing only by finish.

Common external-door buying mistakes

• Confusing leaf size with complete frame size.
• Ordering from one width and height reading only.
• Choosing the wrong handing.
• Ignoring the internal colour of a two-colour uPVC door.
• Assuming glazing is clear when it is obscure, or vice versa.
• Assuming every front door includes the same locks and hardware.
• Buying timber without checking finishing requirements.
• Changing the finished floor or threshold after measuring.

Frequently asked questions

What is the best material for a front door?

There is no universal best material. uPVC is practical and low maintenance, while timber offers natural character and finish flexibility. Compare the exact products against your priorities and project conditions.

What is a common UK front door size?

1981 x 838mm is a commonly encountered external door leaf size, but many other leaf and complete-frame dimensions are used. Always measure your opening and check the product.

Should I buy a door leaf or complete doorset?

That depends on the condition of your existing frame and the product range. Factory-made uPVC doors are commonly complete systems, while timber doors can be sold as leaves. Read the listing carefully.

Is triple glazing always better than double glazing in a front door?

Glazing is only one part of overall door performance. Compare the declared performance of the complete door rather than assuming pane count alone determines the best option.

Can I fit a new front door myself?

Accurate alignment, security, weather sealing and regulatory requirements matter. If you are not experienced with exterior doors, use a competent installer and have the opening checked before ordering.

Where can I compare front doors?

Browse the JJ Building Materials external doors collection and the wider Doors, Bi Folds & Windows range.

Choose your external door with a complete checklist

Measure first, confirm whether you need a leaf or doorset, verify material, glazing, colour, handing, threshold and hardware, then compare the exact product dimensions and manufacturer information. That approach gives you a much stronger result than selecting a front door on appearance alone and helps make your front door replacement smoother from ordering through to installation.