How to Change a Lock on a UPVC Door

Last updated on February 24th, 2021 at 09:21 am

Door locks are vital for keeping your home secure, so it can be a concern when your uPVC door lock barrel starts to struggle. The good news is, changing a barrel locks for PVC doors is a relatively simple task. Here’s our step-by-step guide on how to change uPVC door locks.

Most UPVC doors come with a single “euro-cylinder” lock, and a strip lock or multipoint lock that secures the entire door. After continued use, you may find that the uPVC door lock mechanism is broken or sticking. There are many reasons why a cylinder might break or a multi-point lock might need servicing. For example:

Lock and keys
Door handle
  • If your door drops on its hinges, the locking hooks and bolts on the lock side won’t fit into the keeps on the frame.
  • When the door starts drooping, many homeowners force their doors to lock by lifting the handles to force the hooks into the keeps, causing further damage.
  • Over time, manhandling the door handle causes the lock to fail. The locks cam and spindle can become cracked and damaged.

If your lock is seizing up or clearly already broken, the good news is that you can replace it yourself without too much difficulty. You do not need sophisticated equipment or specialist training to replace a euro-cylinder. uPVC door lock repairs can seem a complicated task but with the right know-how, changing the lock on a uPVC door lock can be tackled quickly and simply.

Tools needed:

Changing upvc door locks is a fairly simple job that does not need a lot of tools. You will need:

  • A screwdriver (Posi drive)
  • The replacement lock
  • Marker pen
  • Tape measure or ruler

Time Required: 30 Minutes

Step by step instructions

Locked door

How to change a lock barrel in a uPVC door: Changing the Euro-Cylinder is a fairly easy job. If the rest of the locking mechanism is broken, however,ย the uPVC door lockย replacement process will be more complex. This assumes that you have already purchased a replacement lock. If you don’t know what size lock to buy, it is a good idea to measure your existing lock (or, if you have someone who can house-sit for you, take the original lock to a locksmith to show them and get a new lock that matches it) rather than trying to make an educated guess.

Note that some older doors have oval or rounded cylinders which look like euro-locks, but are a slightly different design. The euro-locks are a peardrop shape.

  1. Firstly, you should measure the old lock for replacement. The lock should be as close to flush with the door as possible (a few millimetres of protrusion is acceptable). If the lock protrudes a long way from the door then it is too large. Not only does this look ugly, it can pose a security risk.
  2. To measure the lock, open your door and unscrew the retaining bolt on the side of the door. This is the large screw that is in line with the cylinder.
  3. How to remove lock from upvc door: When the screw has been removed, put the key in the lock and turn it slightly until you feel the cylinder release. This may take a little wiggling until you find the right spot. When you feel the cylinder give, you can simply pull the lock out. There should be no resistance.
  4. Put the new lock in the hole and inspect it. If the lock fits well, then you are good to go. If the lock sticks out a long way then it is the wrong size. Draw a line on the lock with a permanent marker where the lock sticks out from the door. Remove the lock and measure the parts of the lock as shown in the image below:
    Measuring the lock
  5. If the lock is too big, you should put the original lock back and purchase a lock that is as close to the dimensions of your door as possible. If you cannot find an exact match, order the next size up.
  6. Once you have a lock that is the right size, line it up and replace the retaining bolt. The easiest way to line up the lock is to put the key in the barrel, push the lock in place and then turn the key so that the bolt comes out about halfway. The bolt will force the lock into the right place, making it easy for you to line the screw up with the hole. This means that when you tighten the screw, you know for sure that the lock is perfectly aligned.Your new lock is ready to use.

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A Few Tips

Before you go to replace your door’s euro-lock, make sure that you have checked the rest of the door and solved whatever underlying issue caused the lock to break. If you do not do this, there is a high chance that the new lock will break quickly. Here’s a quick look at some common faults and how to fix them:

  • If your frame’s keeps are misaligned, you will see abrasions on the keeps on the frame side, and you will struggle to lock the door without lifting the handle upwards to re-align the keeps. You can correct this by adjusting the keeps using an Allen key. If you aren’t sure which keep it is that is misaligned, remove all of the keeps and then replace them one at a time, testing the door as you go to make sure that each keep is correctly aligned.
  • Another common issue is a broken strip lock. If your strip lock is broken, then you will find that the door will not lock using the key at all. A broken strip lock is incredibly difficult to repair, and in most cases you are better off simply purchasing a new one.
  • If your door has slipped on its hinges, then you will need to replace or tighten the hinges and re-align the door in the frame. This may also mean re-aligning the keeps at the same time, and should be done systematically to ensure that the door fits correctly. If the frame is rotten or damaged, you should take care of that at the same time.


Now you know how to change a lock on a door you can keep your home safe and secure. Replacing a euro-lock is a simple job, but before you do it you should figure out why the lock broke in the first place. There is no need to call in a locksmith to replace uPVC door locks, and as long as you have chosen the right lock size you should have no issues.

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