An anti-snap lock upgrade means replacing the euro cylinder in your door with one designed to resist lock snapping, sized so it does not stick out past the handle. The door & hardware federation recommends a TS 007 Kitemarked 3-star cylinder, or a 1-star cylinder used with a 2-star security handle; Sold Secure Diamond cylinders also meet this level. We check your door, measure the cylinder, and fit the right size so the lock works smoothly.
What is lock snapping?
Most uPVC and composite doors use a multipoint lock operated by a euro cylinder: the profile-shaped barrel your key goes into. A standard cylinder has a weak point at the screw hole in the middle. Lock snapping is a well-known attack where the part of the cylinder sticking out of the door is gripped and forced until it breaks at that weak point, exposing the mechanism. We are not going to describe it in more detail than that; the point is that a basic cylinder, especially one that protrudes from the handle, is a weak spot on an otherwise strong door.
How to check your current cylinder
You can do a quick check yourself from outside the door, without removing anything:
- Look at the face of the cylinder around the keyhole. A TS 007 cylinder will carry the Kitemark and a star rating (one or three stars). A Sold Secure Diamond cylinder is marked accordingly.
- Look at the handle for a Kitemark and stars. A 2-star handle or escutcheon combined with a 1-star cylinder gives the recommended 3-star total.
- Check how far it sticks out. The cylinder should be no more than a few millimetres proud of the handle or escutcheon. If it protrudes well beyond, it is likely the wrong size even if it is a good cylinder.
If there are no markings at all, or the cylinder is clearly sticking out, an upgrade is worth considering. Please do not try to remove or drill a cylinder yourself; it is easy to damage the lock, and a door that will not lock is a bigger problem than the one you started with.
What the ratings mean
| Option | What it is | Meets the recommended level? |
|---|---|---|
| TS 007 3-star cylinder | Cylinder tested to the full anti-snap level on its own | Yes, with any suitable handle |
| TS 007 1-star cylinder + 2-star handle | Basic-rated cylinder protected by a security handle or escutcheon | Yes, as a combination |
| Sold Secure Diamond (SS312) cylinder | Independently tested cylinder, also Secured by Design approved | Yes |
| Unmarked standard cylinder | No recognised anti-snap rating | No |
Ratings are only as good as the fitting. A 3-star cylinder that sticks out a centimetre past the handle has lost much of its advantage, and a cylinder that is too short can leave the cam binding. Getting the size right is as important as the grade.
How we fit an anti-snap cylinder
- Measure. Euro cylinders are measured from the centre of the fixing screw to each end, so we measure the inside and outside lengths and the handle thickness rather than guessing.
- Check the lock. A new cylinder cannot fix a door that is out of alignment. If the key is stiff because the hooks are catching on the keeps, we adjust the door too, or the new cylinder will wear just like the old one.
- Fit and test. The new cylinder goes in with the correct cam position, and we test it from both sides, with the door open and closed, several times.
- Hand over keys. You get the new keys, and we suggest how many copies to keep and where.
If you have several doors, keyed-alike cylinders can let one key open them all, which many households find easier. Where a door has a thumb-turn inside, that can be kept, which helps people get out quickly in an emergency without hunting for a key.
Which doors can be upgraded?
Almost any uPVC, composite or aluminium door with a euro cylinder: front and back doors, side doors, and many sliding patio doors and French doors. If the lock itself is worn or the handle is floppy, the gearbox may need attention as well, which our uPVC door lock repair page explains. For composite doors that are catching or dropping, see composite door repair.
Why people in Liverpool ask us for upgrades
Many homes across Merseyside had uPVC doors fitted before anti-snap cylinders were widely used, so the original cylinders are still in place. We are often asked by people who have just moved in and want new keys anyway, and by landlords with rented terraces in areas such as Wavertree, Walton and Bootle who want locks changed between tenancies. It is a short job that fits well alongside other door and double glazing repairs across Liverpool.
We can explain what a cylinder is rated to, but whether a particular lock satisfies your home insurance is for your insurer to decide. Check your policy wording if it mentions specific lock standards.
Want a stronger lock on your door?
Tell us how many doors and send a photo of the cylinder if you can. Call 07777 659786 or leave your details and we will call you back about upgrading the locks, or anything else on our Liverpool window and door repair list.
Frequently asked questions
What is the best anti-snap lock for a uPVC door?
The door & hardware federation recommends a TS 007 3-star Kitemarked cylinder, or a 1-star cylinder used with a 2-star security handle. Sold Secure Diamond cylinders also meet this level. Just as important is the size: the cylinder should sit no more than a few millimetres proud of the handle.
How do I know if my lock is anti-snap?
Look at the face of the cylinder around the keyhole for a Kitemark with stars, or a Sold Secure Diamond marking. Also check the handle for a Kitemark and stars. If there are no markings, or the cylinder sticks out well beyond the handle, it is unlikely to be a rated anti-snap setup.
Can one key open all my doors?
Usually, yes. Cylinders can be supplied keyed alike, so the same key works the front, back and side doors. They need ordering as a set, so we measure each door first. It is a popular choice when people move into a new house and want a fresh set of keys anyway.
Will an anti-snap cylinder fix my stiff door lock?
Not if the stiffness comes from the door being out of line. A key that is hard to turn is often caused by the hooks or rollers catching on the keeps, which strains the cylinder cam. We check alignment and adjust the door when we fit a new cylinder so it turns smoothly.
Can I keep a thumb-turn on the inside?
Yes. Many anti-snap cylinders are available with a thumb-turn on the inside, which lets people unlock the door quickly from inside without a key. That can be helpful for getting out in an emergency. Some people prefer key-both-sides for doors with glass near the lock, which we can discuss.