How to Choose Patio Doors

Under 1.8m — French doors look proportionate. 1.8–3.5m — sliding doors give the cleanest lines with the widest single pane. 3.5m and above — bi-fold or a large 3-pane slider are both viable; the choice is about clear-opening vs closed-state view.

If you'll open the door fully three days a year and look at it 362 days, prioritise the closed-state view — that points at sliding. If you regularly cook and eat with the doors open in summer (kitchen extensions, garden dining), the clear opening of a bi-fold pays for itself in atmosphere.

Georgian and Victorian houses look right with French doors and a Georgian bar overlay. Post-war and 1960s houses suit sliding patio doors — the horizontal proportions match the era. Modern extensions read best with slim-frame sliders or bi-folds and no astragal bars.

Level thresholds turn a patio door into an indoor-outdoor room. All three styles support level-threshold detailing but each needs different waterproofing — French doors use a weathered lip, sliders use a drainage cassette, bi-folds use an inset drainage channel. Get the detail on the drawing before ordering.

Standard aluminium sliding: £1,500–£2,200/m opening. Bi-folding: £1,800–£2,600/m. French doors: £1,000–£1,600/m opening. Slim-frame sliders sit at £2,500–£3,500/m. Prices assume mid-spec double glazing, standard thresholds and RAL colour finish, fully installed with FENSA certification.