How to install the VELUX ZOZ 012K1 security lock

Improve security on centre-pivot roof windows

The VELUX ZOZ 012K1 security lock is a key-operated internal lock designed to add an extra layer of security to compatible VELUX centre-pivot roof windows. When engaged, it helps prevent the window being opened from the inside unless the key is used.

This guide explains what you’ll need, how to check compatibility, and how to fit and test the lock for safe, reliable operation.

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1. Check compatibility first

Before fitting the lock, confirm your roof window type. The ZOZ 012K1 is intended for VELUX centre-pivot windows such as GGL and GGU.

Please note: This lock can’t be used on VELUX top-hung windows or the following models: GPL, GPU, GHL and GHU.

If you’re unsure, check the window data plate (usually on the top edge of the sash when opened) for the model code.

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2. What you’ll need

• VELUX ZOZ 012K1 security lock kit (including key and fixings)
• Phillips screwdriver (or suitable bit/driver)
• Step ladder (if required for safe access)

Always ensure stable footing and safe access to the roof window before starting.

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3. Prepare the window

Open the roof window fully to access the internal frame and sash area where the lock will be fitted.

• Wipe the fitting area clean so the lock sits flush.
• Lay out the lock parts and fixings from the kit.

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4. Position the lock correctly

Hold the lock in place in the recommended fitting position (as per the product instructions supplied with the kit). This is typically on the internal frame where the sash meets the frame, allowing the lock to engage securely.

• Check the lock sits straight and aligns with the closing points.
• Make sure it won’t interfere with normal opening and closing when unlocked.

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5. Fix the lock in place

Using the screws provided, secure the lock base to the window frame.

• If pilot holes are required for your window type, mark the screw positions and drill carefully.
• Do not overtighten — the lock should be firm but not distort the frame material.

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6. Test the lock operation

Once fitted, test the lock to confirm it engages properly:

• Close the window fully.
• Insert the key and turn to engage the lock.
• Check the sash cannot be opened from the inside when locked.
• Unlock and confirm normal operation returns smoothly.

If anything feels misaligned, loosen the fixings slightly, re-align the lock, then re-tighten.

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7. Helpful tips

• Keep the key somewhere safe but accessible, especially for rental properties.
• Fit the lock as part of a wider security approach (lighting, alarms and good access control).
• If you’re unsure about fitting, a roofer or competent installer can fit the lock quickly and safely.

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