French Doors Buying Guide

Standard sizes and configurations

French doors are most commonly sold in pairs, with each leaf around 450mm to 900mm wide, giving an overall opening width typically between 1200mm and 1800mm for a standard two-door set. Wider openings can be achieved by adding fixed side panels or a top light above the doors, which also lets more daylight into the room without increasing the amount of door that needs to swing open.

Height is usually matched to the existing opening, but standard door heights sit around 2000mm to 2100mm. If you're extending an opening or fitting doors into a new build or extension, it's worth deciding on size before the opening is built rather than after.

Master and slave leaf explained

On a pair of French doors, one leaf is designated the master and the other the slave. The master leaf holds the main lock and handle and is the one you open first; the slave leaf is secured by bolts, usually at the top and bottom, and is generally left closed unless you need the full width open.

This matters for everyday use: if you mainly want quick access rather than a full-width opening, make sure the master leaf is on the side that suits your room layout, for example nearer a path or patio seating area.

Opening direction and clearance

French doors can open inward or outward. Outward opening is more common in the UK since it keeps the doors clear of internal furniture and curtains, but it does mean checking there's no obstruction outside, such as a step, railing or narrow patio, that would foul the swing.

Inward opening can suit rooms where outdoor space is tight, but it uses up floor area inside the room and needs curtains or blinds to be positioned to clear the swing.

Side panels and top lights

Fixed side panels either side of the opening doors add width and light without adding more moving parts, and they're a good option where you want a wide glazed feature but don't need the full width to open. A top light above the doors serves a similar purpose, bringing light higher into the room, which suits rooms with lower ceilings where a very tall single door would look out of proportion.

Glazing and thermal performance

As with windows, French doors are available with double or triple glazing, various gas fills such as argon, and low-emissivity coatings. Because French doors have a larger glazed area relative to frame than many other door types, the glazing specification has a real effect on the room's overall heat loss and on comfort near the doors in winter.

For rooms that face the coast, or exposed elevations common across the Wirral, a higher-specification glazing unit with good weatherproofing at the meeting stile between the two leaves is worth the extra cost, since that central junction is where draughts and water ingress are most likely to show up first.

Locking and thresholds

Multi-point locking should run the full height of the master leaf, engaging at several points into the frame, with shootbolts securing the slave leaf top and bottom. Look for cylinders that meet current anti-snap standards, since French doors are a common target point for forced entry given their size and glazed area.

Threshold choice matters for accessibility and weatherproofing. A standard raised threshold sheds water well but creates a step; a low-level or flush threshold suits level access for wheelchairs, pushchairs or simply easier movement between inside and out, but needs careful detailing to avoid water getting in during heavy rain, which is a real consideration in this region.

Material choice

uPVC French doors are the most budget-friendly and low-maintenance option, suiting most modern and many period homes. Aluminium gives slimmer sightlines and a more contemporary look, and tends to handle larger door sizes with less flex. Timber French doors suit period or conservation-sensitive properties, particularly older houses in Chester's conservation areas, but need more regular maintenance to cope with weather exposure.

• uPVC: cost-effective, low maintenance, wide colour range
• Aluminium: slim frames, strong, good for larger openings
• Timber: traditional look, needs regular upkeep, suits period properties

Approximate costs

A standard uPVC French door set in an existing opening typically costs in the region of £1,400 to £2,400, depending on glazing and hardware specification. Aluminium French doors generally run from around £2,000 to £3,500, and timber sets, given the material and finishing involved, can range from about £2,500 upwards. Adding side panels or a top light increases these figures. All prices are approximate and depend on a written quote following survey.

French doors versus patio and bifold doors

French doors give a traditional look and a clear, full-height opening on one side, which suits rooms where you mainly want a defined doorway rather than the widest possible opening. Sliding patio doors take up less internal space when open since nothing swings into the room, and suit rooms where floor space is limited. Bifold doors give the widest possible fully open aperture, folding the panels back neatly, but cost more and need a wider stacking space when open. Which suits you best depends on room layout, budget and how you actually plan to use the opening.

Common questions

Can French doors be fitted with a low threshold for level access?

Yes, a low-level or flush threshold is available, though it needs careful detailing and, in exposed locations, a canopy or good drainage to manage water at the doorway.

Which way should French doors open?

Outward opening is more common in the UK as it keeps the doors clear of internal furniture, but inward opening can suit properties with limited outdoor clearance.

Are French doors as secure as other door types?

A well-specified pair with full-height multi-point locking, anti-snap cylinders and secure shootbolts on the slave leaf offers strong security, comparable to other quality door types.

How do French doors compare in price to bifold doors?

French doors are generally cheaper than bifold doors of a similar width, since bifolds involve more running gear, tracks and panels.