When a UPVC door lock feels too stiff, you’ve lost your key, or moved into a new place, changing the barrel (also known as the Euro cylinder) is one of the quickest ways to restore security.
Here’s a quick expert step-by-step guide.
Step-by-Step Process for changing the barrel on a UPVC door
#1. Open the door fully
Always work with the door open so you don’t accidentally lock yourself out.
#2. Locate the fixing screw
Look along the edge of the door, and locate the faceplate. You’ll see one long screw roughly in line with the keyhole. That is the cylinder retaining screw.
#3. Remove the screw
Use a screwdriver to undo the screw completely. Keep it safe because you’ll reuse this same screw later.
#4. Turn the key slightly
Insert your key and turn it gently about 10–15 degrees. This process lines up the cam (the small rotating piece inside) so the cylinder can slide out. If it won’t move, wiggle the key a touch either way until it slides free.
#5. Measure the old barrel
Measure from the centre of the screw hole to each end of the cylinder on both sides. Cylinders are typically around 40/40mm, 35/45mm, etc. Measure precisely, because UPVC doors are rarely symmetrical.
#6. Fit the new cylinder
Slide in your replacement, align the cam with the latch, and reinsert the fixing screw. Tighten firmly, but don’t overtighten or you’ll pinch the mechanism.
#7. Test the lock
Close the door and test the key from both sides. Make sure it turns smoothly and the handle lifts without stiffness.
Pro locksmith tips
- Upgrade to a 3-star-rated anti-snap cylinder. This product gives much better protection against forced entry.
- Choose the right size so the cylinder face is flush with the handles; overhanging barrels are a burglar’s best friend.
- Lubricate with graphite powder or a silicone-based spray once or twice a year — never use oil.
- A barrel change usually takes under 10 minutes once you’ve done it a few times. It’s an easy way to enhance security and avoid expensive call-outs, but if you’re not sure what you’re doing, call your local locksmith.
