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uPVC Door Won’t Lock – What To Do (Hot or Cold Weather)

uPVC Door Wont Lock

Will your uPVC Door not lock? Are you trying to shut or lock your uPVC door but cannot close the door properly? A uPVC door not locking in cold or hot weather is a very common problem that locksmiths often get called out to fix.

If your uPVC door won’t lock or shut, our guide below should help answer why these common uPVC door lock problems happen.

1. uPVC Door Won’t Lock – Can a Locksmith Help?

A locksmith can definitely help with a uPVC door not locking, many locksmiths work with uPVC and specialise in lock repairs.  So will work on uPVC daily basis and typically will have great knowledge and understanding of how they work.

The locksmith should be able to diagnose the issue within minutes, with a few simple assessments and checks.

2. uPVC Door Won’t Lock When Closed Shut

If your uPVC door won’t lock when closed shut, this is due to alignment and in most cases is easy to fix either by adjusting the lock strike/keep or roller points or by adjusting the door hinges.

A locksmith will usually just charge a labour price for this sort of job, likely to be from £80 per hour.

For average locksmith labour prices see our locksmith prices here.

3. uPVC Door Won’t Lock Even When Open

If your uPVC door won’t lock even when still open this is usually because of the following reasons:

  • uPVC gearbox failure – most common
  • Multipoint lock is damaged
  • Door Alignment Issue
  • Problem with Lock cylinder
  • Door Lubrication is required

uPVC Gearbox Failure

Failure of uPVC Gearbox

uPVC gearbox failure can cause a uPVC Door to not lock when left open.

Most locksmiths will carry a large range of gearboxes with them at all times, due the large ranges available.

The type of job will take from 30 minutes to repair, a uPVC french door maybe take longer especially if the door is a closed position.

Multipoint Lock Damage / Broken

A multipoint lock can stop working if a hook/deadbolt roller/mushroom on the multipoint lock is damaged, in this situation the locksmith would replace the complete multipoint lock.

The cost of a replacement multipoint lock is likely to be anything from £70 to over £240 dependent on the make of lock you have.

uPVC Door Alignment Issue

Poor alignment causes undue wear and tear on the internals of the gearbox/multipoint lock and may cause the gearbox/multipoint to fail.

The price to fix uPVC door alignment is usually just the locksmiths labour charge, likely to be from £80.

Complicated Part of Repairing a Multipoint Lock/Gearbox

The most complicated part of these jobs would be finding suitable alternatives when the multipoint lock/gearbox has been discontinued, there are various alternatives from the leading brands that will cover most of these situations.

4. How long will it take to fix a uPVC Door lock?

The time it takes to fix a uPVC door that won’t lock can take from 15 minutes up to 1 hour depending on what the issue is.

  • If it’s an alignment issue then typically 15-20 mins in normal circumstances.
  • If it’s an issue with the mechanism then that could be anything from 15 mins to an hour.

To Repair uPVC Door Lock

5. How much does it cost to fix a uPVC Door Lock?

The price to fix your uPVC door lock is going to depend on what the issue is.

If an alignment issue then typically the Locksmith will charge for an hours labour + any callout fee – for locksmith costs see our locksmith price list here.

If it’s a mechanism replacement/repair, again that would typically be an hours labour plus the cost of parts + any call out fee.

A locksmith won’t typically know the cost of parts until on-site or if provided with a picture that they may be able to offer an indication of price. It will depend on make, model and whether the part is still available or has been discontinued etc.

How to save money when your uPVC Won’t Lock

Most importantly, it will be cheaper to call a locksmith ASAP rather than leave it until things get far worse or you or a neighbour/family member have a go yourselves.

Leaving the lock will typically increase price in the long run, as what could have been an alignment adjustment issue could then become a repair and replace job.

6. What causes my uPVC door to not lock or open?

There could be many reasons why your uPVC door won’t lock, below are the most common reasons:

Why uPVC Doors won’t Lock or Open

  • uPVC doors are susceptible to expansion and contraction, as is wood and metal.
  • uPVC is probably more common because the multipoint locking systems used in uPVC doors typically have multiple moving locking parts, that locate into varying apertures along the length of the door & frame.
  • A door that is slightly out of alignment, will cause both an issue locking and unlocking.
  • Due to the expansion and contraction, 1mm or 2 out of alignment is enough to stop a door from locking or unlocking.
  • Materials in the locking parts can fatigue and become brittle with age.
  • Weather change can cause parts to break, snap or shatter.

Weather Causes uPVC Doors to Not Lock or Shut

Due to the UK’s weather forever changing and not being stable, from extreme heat in the summer to extreme cold in the winters and anything in between, this can cause problems with uPVC doors.

Cold Weather – uPVC Door Lock Won’t Lock or Shut Properly

Cold and freezing weather will cause a uPVC door to not lock or close properly, this is due to contraction of the uPVC, the shrinking can only be 1mm or 2mm but is enough to stop your door from locking.

Hot & Warm Weather – uPVC Door Lock Won’t Lock or Close

Hot weather can cause your uPVC door to not lock due to the uPVC expanding in warm weather, which causes the door to become stiff, so it will become difficult to shut or open

7. What should I do when my uPVC door won’t lock?

The best thing anyone can do is to leave it as it is and call in a locksmith uPVC specialist ASAP.

Not doing anything to your door lock will ensure no further issues are created, It also allows the locksmith to see what’s caused the issue in the first place and then best advise.

If your problem is key is stuck in lock click here.

upVC Door Not locking

8. What NOT to do with a uPVC Door Lock Problem

Below are things you SHOULD NOT do if your uPVC door will not lock or shut properly:


Forcing the lock or handle can cause additional problems such as damaging the mechanism, door handle or even marking the door and frame. This will cause additional unnecessary damage and potential extra costs.


Don’t allow neighbours or friends to attempt to help fix your uPVC door lock, unless they have knowledge or experience in the field.

Important: The locksmith will not know what necessarily caused the issue in the first place if you attempt to fix yourself.


Don’t just leave your door lock in the hope it will remedy itself when it warms up, this will be a temporary solution to the problem.

As soon as the weather gets cold again, the issue with the lock issue will return.

uPVC Door Lock Repair

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