Introduction

French doors are designed to last for many years, but like any frequently used door, their locks and moving parts eventually wear. A door that becomes difficult to lock, won't open properly or has a stiff handle doesn't usually need replacing. In most cases, the problem can be repaired by replacing worn components and correcting the underlying cause.

The key to a successful repair is identifying exactly what's failed and ensuring the doors are correctly aligned afterwards. Replacing parts without addressing the cause often leads to repeat failures.

Here are some of the most common French door repairs we carry out.

Door Realignment

One of the most frequent repairs is correcting French doors that have dropped or moved out of alignment.

A misaligned door can cause:

• Difficulty lifting the handle.
• The key becoming stiff.
• The doors catching the frame.
• Locking points failing to engage correctly.
• Draughts around the doors.
• Premature gearbox wear.

Once correctly adjusted, the doors usually lock, unlock and operate much more smoothly.

Gearbox Replacement

The gearbox is the heart of the multipoint locking system and one of the components most likely to wear over time.

Signs of gearbox failure include:

• The handle lifts but nothing happens.
• The key turns without unlocking the door.
• The locking points remain engaged.
• The handle feels loose or floppy.
• The door becomes locked shut.

If the remainder of the mechanism is in good condition, replacing the gearbox is often the most economical repair.

Complete Multipoint Mechanism Replacement

Sometimes the damage extends beyond the gearbox.

We replace complete locking mechanisms when there is:

• Extensive internal wear.
• Broken connecting rods.
• Damaged hooks or rollers.
• Seized locking points.
• Door difficult to lock.
• Damaged faceplates.
• Obsolete mechanisms that cannot be repaired.

Replacing the complete mechanism restores reliable operation while retaining the existing doors.

Lock Cylinder Replacement

A worn lock cylinder can make the key difficult to turn, insert or remove.

Common reasons for replacement include:

• A stiff key.
• Worn internal pins.
• Lost or stolen keys.
• Security upgrades.
• Failed or damaged cylinders.
• Cylinders protruding beyond the handles.

We can also upgrade older cylinders to modern snap-resistant locks that provide protection against lock snapping, drilling, picking and bumping.

Handle Replacement

French door handles receive constant daily use and eventually wear out.

We regularly replace:

• Loose handles.
• Drooping handles.
• Broken sprung handles.
• Damaged backplates.
• Worn handles affecting lock operation.

Quality sprung handles also reduce strain on the locking mechanism and help extend the life of the gearbox.

Slave Door Repairs

Many French door faults actually originate with the secondary (slave) door.

Common repairs include:

• Shoot bolt repairs.
• Replacement shoot bolts.
• Slave door adjustments.
• Faulty locking mechanisms.
• Doors that won't release properly.
• Misaligned locking points.

Repairing the slave door often restores the operation of the complete door set.

Opening Jammed French Doors

If your French doors won't open, it doesn't automatically mean they'll need replacing.

Common causes include:

• Failed gearboxes.
• Broken multipoint mechanisms.
• Seized locking points.
• Faulty slave door locks.
• Internal mechanism failures.
• Misalignment.

In many cases, the doors can be opened and repaired without unnecessary damage.

Obsolete Lock Mechanisms

Many older French doors contain locking mechanisms that are no longer manufactured.

Depending on the make and model, it may still be possible to:

• Source replacement mechanisms.
• Fit compatible alternatives.
• Upgrade the locking system.
• Adapt suitable replacement components.
• Replace individual gearboxes.

Many obsolete locks can still be repaired without replacing the doors.

Security Upgrades

Many homeowners choose to improve security while repairs are being carried out.

Popular upgrades include:

• Snap-resistant lock cylinders.
• TS007 security handles.
• High-quality sprung handles.
• Replacement multipoint mechanisms.
• Insurance-approved locking systems.
• Keyed alike lock systems.

Upgrading security during a repair is often more cost-effective than arranging a separate visit later.

Every Repair Includes Checking the Door Alignment

Replacing a gearbox or locking mechanism is only part of a professional repair.

After fitting replacement parts, the doors should always be checked and realigned where necessary.

Correct alignment helps:

• Reduce strain on the new mechanism.
• Allow the handles to operate smoothly.
• Ensure every locking point engages correctly.
• Improve weather sealing.
• Extend the life of the replacement parts.
• Prevent repeat failures.

Ignoring alignment is one of the most common reasons replacement gearboxes and mechanisms fail prematurely.

Preventative Repairs Save Money

Many major French door failures begin with relatively minor symptoms.

Watch for:

• A stiff handle.
• A key that's becoming difficult to turn.
• Doors catching the frame.
• Handles that don't return properly.
• Locking points feeling tight.
• Unusual clicking or grinding noises.

Addressing these problems early is often far less expensive than waiting for the mechanism to fail completely.

Repairing Rather Than Replacing

One of the biggest misconceptions is that faulty French doors need replacing.

In reality, most repairs involve replacing worn components while retaining the existing doors.

Whether the fault is:

• A dropped door.
• A failed gearbox.
• A worn lock cylinder.
• A damaged multipoint mechanism.
• A faulty slave door.
• Worn handles.

the correct repair will usually restore smooth, secure and reliable operation at a fraction of the cost of installing new French doors.

Conclusion

Most French door faults are mechanical rather than structural, making repair the most practical and cost-effective solution. From realigning dropped doors and replacing worn gearboxes to fitting new multipoint mechanisms, repairing slave doors and upgrading security, the majority of problems can be resolved without replacing the doors themselves. A proper diagnosis, quality replacement parts and correct door alignment ensure a long-lasting repair that restores smooth operation, reliable security and many more years of service.