How to Choose French Doors

French doors work best on openings of 1.2m to 1.8m wide. Below that, a single glazed door and a fixed side-light usually looks better. Above 1.8m, the leaves become heavy enough to sag over time and you get more benefit from sliding or bi-folding doors. The clue is the room behind: French doors suit rooms you'll walk out of, sliders suit rooms you look out from.

In the UK most French doors open outwards to save internal floor space. Inward opening becomes worth considering on exposed elevations (weather seals sit inside the rebate, which resists driven rain better) and on Juliet balconies where outward swing is impossible. Confirm the swing direction on the drawing before the door goes into production — it can't be reversed after manufacture.

Standard French-door thresholds sit 40–60mm above finished floor. If you want a near-level threshold — for wheelchair access, for garden flow, or just to avoid tripping — ask for a low-threshold or 'weathered lipped' option. These are typically rated to slightly lower weather ratings, so best used on sheltered elevations.

A well-specified French door has an active leaf with a multi-point locking system (5 points minimum), a passive (slave) leaf with shoot bolts top and bottom, and a TS007 3-star cylinder. Cheap French doors save money on the passive leaf, leaving it held only by a friction stay — which is what burglars target.

Georgian bars (interior applied) suit period homes, chunky external astragal bars suit heritage settings, and clear unbroken glass suits contemporary extensions. Toughened glass is required to Building Regs in any pane below 800mm from floor. For south-facing rooms, request solar-control glazing to reduce summer overheating without darkening the glass.