My uPVC door won't lock - What do I do?

My uPVC door won't lock...

First of all, check these three points:

• Is it hot or cold weather?
  In the peak cold or warm months, it's common for a uPVC door to expand in heat or contract in severe cold. Repeatedly wiping the door with a cloth soaked in warm or cold water will get it back to its natural state.
• Is there anything blocking the door frame? 
  Check for any blockages on the outside of the door, as well as the frame of the doorway. The door may engage a lock at multiple points, so be sure to check all locking points are clear. Also, make sure that nothing is caught on the bottom edge of the door.
• Is the lock snib engaged? 
  The snib is a button or switch that holds the locking bolt in or out. If the snib is engaged, release it to be able to lock the door.

uPVC door won't lock when closed

If your door won't lock when it's closed, the latch might not be catching or engaging. Test the spring mechanism in the door by opening the door and pressing the latch with your finger:

• If the latch springs out, it may be out of alignment or shifted slightly.
• If the latch doesn't spring out, the springing mechanism may have failed and would need to be replaced.

A few other reasons this could happen are:

• Fluctuations in temperature. Wipe a cloth soaked in warm water (in cold conditions) or cold water (in warm conditions) around the door to combat it expanding or contracting.
• Dropped door. If the door is angled slightly, it would need to be levelled to ensure that it sits flush with the frame.

If the door appears to be out of alignment, you can try to adjust the hinges to re-enagage the latch. Read how to adjust uPVC door hinges here.

uPVC door key won't turn all the way (or insert into the lock)

• Are you using the right key? As obvious as this may be, sometimes the simplest solution can fix the problem.
• Have you recently got a key cut? If a newly-cut key doesn't insert into a door, it may have been poorly cut. Contact the locksmith that you got the key from as most will offer a replacement key free of charge.
• Is there debris in the lock? You may be able to remove the debris carefully using thin wire, such as fishing line or guitar string.
• Is the key bent? The locking mechanism will only work when the key is straight, so get a new one cut or use a small blunt object to straighten it out.
• Is the door or key worn, old or cracked? A door's locking mechanism or a key could be faulty due to many years of service. If the key is worn, a locksmith may be able to cut a replacement for you.