Introduction

The way that your window opens determines what sort of security fittings you should use so that the opening mechanism can be obstructed, and thus prevent the window from opening.

There are also specific fittings for use on the various window frame materials, so ensure that you select the right ones for your range of windows. In addition to selecting the right mechanism, window furniture is often available in a range of finishes, such as brass, chrome, nickel and white enamel to best complement your interior.

Window locks must be strong enough to resist being forced. To optimise their strength, a lock should be placed in the centre of a small window, or two locks should be spaced apart on a large window.

Locks operated by a removable key are the most secure, especially if the key has several variations, rather than a standard profile.

Hinged windows

Hinged windows are usually locked by fastening the moving sash to its static frame.

The most commonly used furniture on hinged windows are stays and fasteners, or cockspur locks. A stay is placed at the bottom edge of the window, where its notches can also be used to secure the window while open.

On reasonably large windows a fastener, or cockspur lock, should also be mounted on the opening side of the window, where the lock's protruding bolt then fits into a mortice, or hole, cut into the frame to prevent opening.

Sliding windows

Sliding windows are often locked to one another so that neither can be moved within the frame. Most locks for these types of windows are designed for boxsash windows, but the locks can equally be used on horizontally sliding windows too.

For an inconspicuous look, a dual screw sash bolt should be used which passes through both sash frames at the ‘meeting rails’. This bolt is unscrewed using a special key so the bolt can be removed and the windows become decoupled. The same end result can be achieved using a sash fastener that is mounted to the top of the bottom window and the bottom of the top window, preventing the two from being separated.

Sash stops allow a sash window to be opened for ventilation, but prevent the window from being opened further to allow an intruder in or out. With the windows closed, a pair of stops should be fitted to the frame of the top window within about 127mm (5in) of the top of the closed bottom window. With the stops in place, the bottom window can only be opened this far, but the stops can be completely removed with a key to allow the window to be opened fully.

Pivoting windows

Most pivoting windows are supplied with integral locks built into their frame. However, where they are missing, or you require additional security, several standard locks that attach the moving sash to the static frame can be used.

The simplest is a push lock that uses a steel bolt to fix the window to its frame, locking automatically as it is pushed in, and requiring a key to unlock.

Further information and useful links

• Types of window
• Types of glass
• Window frame materials
• Common sizes of window
• Window requirements of the building regulations
• Full list of windows & doors topics

• Find a Double Glazing supplier near you
• Find a Sash Window supplier near you
• Find a Carpenter near you
• Find a Window Furniture supplier near you