French doors in Leicester: what you're actually buying

What a French door actually is (and what it isn't)

A French door is a pair of hinged doors that meet in the middle with no central mullion, so when both leaves are open you get the full structural opening. One leaf is the master — it carries the handle and the multi-point lock. The other is the slave, held top and bottom by shootbolts you release by hand.

That definition matters because it separates French doors from the two things buyers most often confuse them with. A patio door slides on a track, so one half of the opening is always filled by a panel. A bifold folds and stacks, giving you almost the whole opening, but it runs on a bottom track with rollers and costs considerably more. If someone quotes you 'French doors' and the drawing shows a track, it is not a French door.

The other point people miss: French doors can open inwards or outwards, and the choice is not cosmetic. Outward-opening is the default in the UK because it wastes no internal floor space and sheds water away from the threshold. Inward-opening is worth considering where the doors give onto a narrow patio, a step down, or a passageway where a swinging leaf would foul a bin or a path.

Sizing: the numbers you need before anyone quotes

The single most common false economy in French door buying is measuring the doors instead of the opening. What we survey is the structural opening — brick to brick, and the level of the floor inside and out. Everything else follows from that.

Standard pairs in the UK come in a well-worn set of widths, and staying close to one of those is the cheapest route. Going wider than about 1,800mm on a pair without side panels means each leaf is over 900mm, which puts real weight on the hinges and, on a windy Leicestershire garden, real load on your wrist every time you open it.

• Structural opening width, brick to brick, at three heights
• Structural opening height, at both jambs and the centre
• Whether the floor inside is level with, above or below the outside
• Which way the doors need to swing and which leaf you want as master
• Whether a cill, a low threshold or a flush threshold is needed

Thresholds — the detail that causes the most arguments

A standard French door threshold has an upstand. It seals well, it drains well, and you step over it. A low threshold reduces that upstand to something a wheeled item can cross. A fully flush threshold removes it altogether and relies on drainage below the frame.

The trade-off is honest and worth stating plainly: the flatter the threshold, the harder it works to keep driving rain out. On an exposed elevation we will always recommend a standard or low threshold rather than a flush one, and we will tell you so at survey rather than after the first storm. If accessibility genuinely requires flush, it can be done, but it needs the outside ground level and the drainage sorted at the same time.

Security on a pair of doors

The weak point on any French door is the slave leaf. On a badly specified pair, the slave is held by two thin shootbolts into a plastic keep, and the whole set can be sprung. On a properly specified pair, the master leaf carries a multi-point lock with hooks and rollers, the slave carries full-height shootbolts into steel keeps at head and cill, and the hinges are bolted so the pins can't be driven out.

Our French doors are supplied with PAS 24 tested hardware and, where a cylinder is fitted, a TS007 three-star cylinder that resists snapping. Those are the two standards worth checking on any quote, from us or anybody else — PAS 24 is the door set test, TS007 three-star is the cylinder test, and a door can pass one while failing on the other.

What £1,499 fully fitted covers

Fully fitted means fully fitted. That price is for a made-to-measure uPVC French door pair in white, A-rated double glazing with a warm-edge spacer, multi-point locking, our own installers, and the whole job done end to end.

Where the price moves is predictable and we will tell you at survey: a coloured or woodgrain foil on the outside, side panels, toughened or obscure glass beyond the safety-critical minimum, an integral blind, a bespoke wide opening, or structural work if the existing lintel is failing.

• Made-to-measure uPVC French door pair with A-rated glazing
• Multi-point locking on the master, full-height shootbolts on the slave
• Removal of the existing door or window and frame
• Fixing plumb and square, packed properly rather than foamed
• Internal and external sealing and making good at the reveal
• Disposal of all old materials
• 10-year insurance-backed guarantee registered to your address

Timings, and what happens on the day

A single French door replacement is a one-day job in almost every case. The old unit comes out in the morning, the new frame is in and sealed by early afternoon, and the rest of the day is glazing, adjusting the lock, and making good.

Between quote and fit, the manufacturing lead time is the long pole. A white standard-size pair is quick; a coloured, non-standard or side-panelled set takes longer because it is made specifically for your opening. We give a firm date at the point of order rather than a hopeful one at the point of quote.

Three ways French door quotes are made to look cheaper

First, the glass. A pair of doors has large panes, and glass is where cost hides. A quote that doesn't state the unit spec, the spacer type and the energy rating is not comparable with one that does.

Second, the fitting. 'Supply only' or 'supply and fit, making good by others' means the plaster, render or brickwork at the reveal is your problem. On a French door that is not trivial, because the opening is wide.

Third, the guarantee. An installer's own guarantee is worth exactly as long as the installer trades. An insurance-backed guarantee is underwritten, so it survives them. Ours is a 10-year insurance-backed guarantee registered against your property.