French doors in London, the garden, both doors wide.

A french door is two glazed leaves hinged at the sides, meeting in the middle with no fixed post between them. Open both and you get the entire aperture, something a sliding door never gives you, in a format that suits London's Victorian and Edwardian rear rooms far better than a wall of folding glass. The symmetry flatters period proportions, the glazed leaves pull garden light deep into the plan, and with the leaves shut the room still reads as two tall windows.

They are also the honest recommendation for smaller openings. Under about 2.4 metres a bifold becomes two cramped leaves and a slider only half-opens, while a french pair, alone or with slim fixed side panels, gives a clear opening and a better price. Every set is made to measure in our sister factory rather than pulled from stock sizes, so awkward brick openings are simply what we measure, not a problem to pad out.

French door installation starts with a free survey: we measure the structural opening, check the lintel, agree the swing (outwards is the London default, inwards where a balcony or path demands it) and pick thresholds, colours and glass. Frames are then made to the millimetre by our sister company Prime Fabrication, factory direct with no middleman, and arrive in around 2-3 weeks.

Fitting an existing opening takes about a day. The pair is hung so the leaves meet dead level, the multi-point lock and slave-leaf shootbolts are adjusted to throw smoothly, and the frame is sealed inside and out. Every installation is FENSA certified, so the Building Regulations certificate arrives without paperwork on your side, backed by our workmanship guarantee. Security is built in rather than bolted on: hook locks on the lead leaf, shootbolts top and bottom on the slave, hinge protection and toughened or laminated glass throughout.