French doors that won't open can be frustrating, especially if they're locked shut or only one door will open. While it's tempting to force the handle or key, this often causes more damage and turns a simple repair into a more expensive one.

The good news is that most French door faults can be repaired without replacing the doors.

Check What's Actually Happening

Before doing anything, identify the symptoms.

Ask yourself:

• Does the key turn?
• Does the handle lift?
• Is the handle floppy?
• Is only one door affected?
• Are the doors unlocked but still won't open?

The answers will often point towards the cause.

The Gearbox May Have Failed

A failed gearbox is one of the most common reasons French doors refuse to open.

Typical symptoms include:

• The handle moves but nothing happens
• The key turns but the lock stays engaged
• The locking points don't retract
• The door remains firmly shut

In many cases, the gearbox can be replaced without replacing the entire locking mechanism.

The Slave Door May Be the Problem

Many French doors consist of a main door and a secondary (slave) door.

If the slave door develops a fault, you may notice:

• Shoot bolts won't retract
• Only one door opens
• The doors feel jammed together
• The main door won't release

Often, repairing the slave door restores the operation of both doors.

The Doors May Have Dropped

Over time, French doors can move slightly on their hinges.

Signs include:

• The doors catching the frame
• Difficulty lifting the handle
• Having to push or pull the doors
• Uneven gaps around the frame

Misalignment places extra strain on the locking mechanism and can eventually cause it to fail.

A Broken Handle

If the handle feels loose, floppy, or doesn't return properly, it may have failed.

While a broken handle can prevent the lock from operating correctly, it's important to remember that a failed gearbox often causes similar symptoms.

A proper diagnosis is essential.

Don't Force the Handle or Key

Using excessive force can result in:

• A snapped key
• Broken handles
• A damaged gearbox
• Bent locking points
• Damage to the door

If the lock won't operate normally, forcing it is unlikely to solve the problem.

Check for a Stiff Lock Cylinder

If the handle feels normal but the key is difficult to turn, the lock cylinder may be worn or damaged.

Common signs include:

• The key sticking
• Rough operation
• Difficulty removing the key
• The key turning inconsistently

Replacing the cylinder is often a straightforward repair.

Most French Doors Can Be Repaired

Many homeowners assume they need new French doors when they stop opening.

In reality, the fault is often caused by:

• A failed gearbox
• A dropped door
• A worn lock cylinder
• A broken handle
• A faulty slave lock
• Misaligned locking points

Most of these problems can be repaired without replacing the doors.

Prevent Future Problems

French doors usually give warning signs before they fail completely.

Watch for:

• A stiff key
• A heavy handle
• Difficulty locking
• The doors catching the frame
• Locking points sticking

Dealing with these issues early can help prevent an unexpected lockout.