The Ultimate Guide to Measuring a UK Door Lock for Replacement

Whether you're moving into a new home or just looking to upgrade your security, replacing a door lock is a common task for homeowners. However, to ensure a seamless and successful replacement, it's crucial to measure the existing door lock accurately. In this guide, we'll walk you through the step-by-step process of measuring a UK door lock, including all the essential measurements you'll need to find the perfect replacement.

Tools You'll Need:

Before we dive into the measurements, gather the following tools to make the process easier:

1. Tape Measure: A reliable tape measure will be your best friend throughout this task.

2. Screwdriver: You might need this to remove the existing lock from the door.

3. Notebook and Pen: Take notes of the measurements as you go along, to avoid any confusion.

Step 1: Identify the Type of Lock

There are several types of door locks in the UK, and the measurements may vary slightly depending on the lock's design. The most common types include:

• Mortice Locks

• Euro Cylinder Locks

• Rim Locks

• Nightlatches (Yale Locks)

Identifying the type of lock will help you understand which measurements are essential for finding a suitable replacement.

Step 2: Measure the Backset

The backset refers to the distance from the edge of the door to the centre of the keyhole or the spindle (the part that turns with the key). The standard backset in the UK is 57mm, but it can also be 45mm or 70mm in some cases.

To measure the backset, follow these steps:

1. Close the door and locate the centre of the keyhole or the spindle.

2. Measure from the edge of the door to the centre of the keyhole or spindle.

Step 3: Measure the Lock Case Length

For mortice locks, you'll need to measure the length of the lock case, which is the metal box that fits into the door.

1. Open the door and locate the lock case on the side of the door edge.

2. Measure from the front plate (where the latch bolt comes out) to the back of the lock case.

Step 4: Measure the Overall Length

This step is applicable for Euro cylinder locks.

1. Locate the centre of the screw that secures the Euro cylinder on the inside part of the door.

2. Measure from the centre of the screw to the outer edge of the cylinder on both sides.

Step 5: Measure the Cylinder Length

For Euro cylinder locks, you'll need to measure the length of the cylinder itself.

1. Remove the existing Euro cylinder from the door.

2. Measure from one end to the other end of the cylinder.

Step 6: Determine the Cylinder Type

While examining the Euro cylinder, take note of its shape and whether it has a single, double, or thumb turn mechanism. This information is crucial when choosing a replacement.

Step 7: Measure the Case Height and Width

For rim locks and night latches, you'll need to measure the case height and width.

1. Measure the height from the top to the bottom of the lock case.

2. Measure the width from the left to the right side of the lock case.

Step 8: Note Down Additional Features

Finally, make a note of any additional features or specifications that your lock might have, such as security ratings (e.g., BS3621), fire-rated certification, or any brand-specific information.

Conclusion:

By following these simple steps, you can accurately measure a UK door lock and find the perfect replacement. Remember to double-check your measurements before purchasing a new lock to ensure a smooth installation process. Improving your door's security is a smart investment, providing you with peace of mind and safeguarding your home and loved ones.