French door installation, and where the leaves will swing

What is french door installation?

French door installation fits a pair of hinged, glazed doors into one opening. Day to day, one leaf is the active door you use; the other is held shut by flush bolts into the head and floor and opens only when you need the full width. The join between them is closed by an astragal. Getting the handing, the swing direction and the floor clearance right at the quoting stage is what separates a pair you enjoy from one you stop opening.

Signs you need french door installation

• You want the full opening usable at once - moving furniture, entertaining, carrying things through - which a slider with a fixed panel cannot give you
• You are replacing a tired slider and the room has floor space to spare on one side
• You want to divide two interior rooms while keeping the light and the sightline - a study, a dining room, a bedroom off a landing
• A single door is too narrow for the traffic through it, and a single wide leaf would be too heavy to swing comfortably
• You want a door pair that can be locked open on a fine day, which swinging leaves do and sliders do not

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How french door installation actually works

1. 1

   Handing and swing decided on the floor, not on paper

   Handing is which leaf is active and which side its hinges are on. Swing is whether the pair opens into the room or out of it. Both are set at the point of order and cannot be changed afterwards on a pre-hung exterior pair.

   Watch forA handing chosen by whoever fills the order form. Stand in the doorway, walk through it, and decide which side you naturally reach for. Then mark the swing arc on the floor with tape and leave it there for a day.

2. 2

   In-swing versus out-swing, on an exterior pair

   Out-swing sheds weather better and gives you the floor space back, which is why it is common in wet and windy locations. In-swing keeps the hinges inside where they cannot be attacked and is the default in most of the US.

   Watch forOut-swing exterior doors with ordinary hinge pins on the outside. If you go out-swing, the hinges must be non-removable-pin or have security studs, or the whole door can be lifted off.

3. 3

   The astragal and the locking arrangement

   The astragal is the vertical closer strip on the inactive leaf that the active door shuts against. On an exterior pair, that inactive leaf is held by flush bolts top and bottom, and the active leaf locks into the astragal. Multipoint locking, which throws bolts at several heights, is the stronger arrangement on tall glazed pairs.

   Watch forFlush bolts that engage into nothing but the threshold surface. The bottom bolt should drop into a proper socket, and the top into the head jamb - otherwise the inactive leaf flexes and the pair rattles.

4. 4

   Setting the unit, and the reveal down the middle

   The frame is shimmed plumb at both hinge sets and at the strike, fastened through the shims, and then the gap between the two leaves is checked top to bottom. That centre reveal is the one thing everyone looks at afterwards and it is the hardest thing to fix later.

   Watch forA tapered centre gap - wider at the top than the bottom or vice versa. It means the unit is racked, and shimming after the trim goes on is far harder than shimming before it.

5. 5

   Threshold, sill pan and weather seal on exterior pairs

   A sill pan under the threshold drains anything that gets past the door back outside. The threshold is then adjusted so both leaves compress their sweeps evenly, and the perimeter is insulated and flashed.

   Watch forNo pan under a glazed pair. French doors present a lot of glass and two sweeps to the weather, and the bottom corners are where water finds its way in.

6. 6

   Hardware, glass and finishing

   Handles, deadbolt and any multipoint mechanism are fitted and tested; on exterior pairs the glass is tempered as standard. Trim goes on inside and out, and the doors are cycled repeatedly to confirm they still close evenly.

   Watch forDoors that meet at the top but not the bottom after a few dozen cycles. Glazed leaves are heavy and hinges settle. Ask for a follow-up adjustment to be part of the deal.

What does french door installation cost?

French door installation typically runs $1,500 to $7,000 fitted. Labour alone on a straightforward same-size exterior pair is a few hundred dollars; converting a slider opening, widening, or specifying multipoint locking and clad wood pushes it toward the top.

See the full french door installation cost guide - by material, size and region →

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