Improve Your Window Security

Window Security

window security You may think that even if you do secure your windows with locks that a burglar would simply break through the glass. Fortunately, when given the choice, most burglars would rather not smash out a window pane and climb through the resultant mess. Breaking through glass takes time and, importantly, makes quite a lot of noise, increasing the risk of discovery. The major problem for a burglar in this situation, however, is the strong possibility that he might leave valuable forensic evidence behind him, such as fingerprints, clothing fibres, shoe prints and blood (leading to DNA). Moreover, microscopic shards of glass will be trapped in his clothing and can be matched to those of the window, tying him directly to the offence.

Making a burglar use a tool to force open a window can further help the forensic scientists, as they are often able to match the marks it leaves to those found at the scenes of other burglaries and to the tool itself. In other words, a well-locked window will help to prevent a crime from occurring in the first place, and if it does fail and the burglar breaks through the glass, the chances are that he will be tracked down after the event.

There are three methods of breaking through a window: forcing it open with a lever – made much easier when no locks are fitted; breaking through the glass; and, particularly with some replacement double-glazed windows, removing the entire frame. That said, a surprising 15 per cent of burglaries (some 200,000 each year) involve no forcing at all – the burglar simply opens an unlocked door or climbs through an open window!

There’s an enormous range of window locks designed for every type of window and most window materials, and you’ll find exactly what you’re looking for at a locksmith’s or large DIY store. The vast majority are very easy to fit, so there are no excuses for insecure windows. This section covers the most common types, although there are some specialised locks for aluminium and plastic double-glazed windows that will only be available from a locksmith.

The majority of window locks use common keys. In other words, one key will open an entire range of locks. This is not a problem because to gain access to the lock, the burglar has to smash the glass, and if he’s done that, he might as well come through it rather than waste time fiddling with the window lock. Moreover, different ranges have different common keys, and because there are so many to choose from, a burglar would have to carry a large bunch to cover all eventualities. Special locking and opening devices for doors and windows belonging to the disabled can be obtained through a master locksmith.


High-Security Windows

The window security standard is pretty much the same apart from the fact that it has been developed to a full British Standard Kitemark – BS 7950: 1997. The Kitemarked windows will have undergone a similar range of tests as the PAS 24 door sets.

A BS 7950 window fitted with 6.4mm laminated glass and multi-point locking, with key operation in the opening handle, offers a high degree of protection against burglary, but as with door sets, it is essential to realise that the tests and the Kitemark cover the whole window and not individual components, such as the locks or hinges, so beware of misleading claims.

If you have moved into a new home in the past five years, the chances are that the ground-floor windows and any others that are accessible by climbing, will be BS 7950 Kitemarked, or at least have been tested to this standard. Although the Association of British Insurers (ABI) and its members, and other insurers who are not ABI members, recognise the standard, you must check with your own insurer to satisfy yourself that your windows meet the minimum security standards set by the company.


Which Windows Should Meet the Standard?

If it means saving a little money on replacement windows, you can restrict the use of BS 7950 windows to those that are on the ground floor, on an open balcony access, on a shared roof terrace or roof garden, or otherwise accessible by climbing. These windows should have key operation of the locks (which will almost certainly be a multi-point locking system with the key cylinder in the handle) and be glazed with a minimum of 6.4 mm laminated glass on the inner pane.

Changes to the Building Regulations required that at least one window of appropriate size in each habitable room (not bathrooms, hallways or kitchens) must be available for emergency escape and must not be fitted with a key operated lock. So, instead of a key on the operating handle, you’ll find a simple button, which must be pressed before you can turn the handle. In these circumstances, any glazing must be laminated to 6.4 mm minimum thickness. This change won’t affect you unless you have new windows installed or you move to a brand-new house. For safety, consider having opening restrictors on windows above the ground floor.

If safety glass is required for any of the windows, make sure that you use the laminated glass equivalent for the inner pane. The outer pane can be toughened, but note that toughened glass is not a security glass.


Leaded Light Windows

If your windows have traditional leaded lights (small pieces of glass held together by strips of lead), you should still fit locks, but understand that it is easy to break through this type of glazing without making much noise. It may be possible to have security grilles made for the most common diamond-design leaded lights, which will be hidden behind the lead strips, but these will be expensive. You could also consider secondary glazing using laminated glass. If you are not keen on these physical solutions, consider having an alarm installed.


Sliding Sash Windows

The sliding sash window is very common, comprising two glazed frames (sashes) that slide up and down within an outer frame. To make light work of sliding the sashes, each is attached by cords to counterweights that run up and down inside the hollow sides of the outer frame.

Unfortunately, age and poor maintenance lead to a lot of these windows not sliding very well. When in good condition and correctly locked, they can slow the progress of a burglar or even deter him completely.

Sash windows suffer from a number of security weaknesses, but nothing that can’t be easily remedied. Many are not fitted with key locks, relying solely on a pivoting catch that bolts the sashes together where their frames meet in the centre of the window. In some cases, it is possible to insert a thin blade of some sort between the two sashes from the outside to knock the bolt across.

Some sash windows simply don’t close properly due to a build-up of paint, or distortion caused by the swelling or shrinking of the timber. This can result in gaps above or below the sashes that are large enough to allow insertion of a substantial lever, such as a spade or crowbar. Too much paint and distortion can also prevent certain types of lock from functioning.

Sash windows can be secured by three basic types of window lock: the dual screw, lockable sash stop and frame-to-frame fixing.


Dual Screws

Most dual screws comprise a part-threaded bolt, which screws through an internally-threaded barrel located in the top rail of the inner (lower) sash. As the bolt is screwed in, its plain end passes into the bottom rail of the outer (upper) sash, preventing the sashes from sliding past each other. The cheapest (and most common) type of dual screw simply passes through a keep plate and into a hole drilled in the outer sash, whereas the more expensive type has a completely threaded bolt that screws into an additional threaded barrel in the outer sash. It is not uncommon for the part-threaded bolts of the cheaper types to bend or break through the rail when great leverage is applied to the bottom sash.

Another disadvantage of the dual screw is that sash windows have a tendency to swell and shrink slightly during the year, which can make aligning the components difficult. It’s also possible to cut through the bolt by inserting a thin hacksaw blade between the sashes, although this rarely happens. The main problem usually lies with the fitting, however, especially when the keep plate is not used on the outer sash, because this makes it easier to force the bolt right through the rail.

If you want to use dual screws on modern sliding sash windows, which also tilt inwards for cleaning, and run up and down on metal sliders, you will have to fit the all-threaded type. This lock will prevent the window from going up and down and tilting inwards.


Sash Stops

Equally common as the dual screw, and arguably more secure than the cheaper varieties, is the lockable sash stop. This is fitted in pairs to the stiles of the outer sash; when the removable or retractable bolts are engaged, they prevent the sashes from passing each other. They can be fitted around 100 mm (4 in) above the top rail of the inner sash (when the sashes are closed) so that the window can be opened a little for ventilation while remaining locked. To prevent damage to the tops of the stiles of the inner sash by the bolts, metal plates are usually supplied. Some Victorian and Georgian sashes, however, often have a decorative finish to the tops of the stiles, making it difficult, if not impossible, to fit the plates. Vulnerable windows should be fitted with two pairs of sash stops or two pairs of locking points: one to lock the window in the closed position, and the other to allow the window to be opened partially for ventilation. The latter should only be done when someone is home; if you go out, lock all windows closed.

There are two basic types of lockable sash stop. One comprises a threaded barrel that is inserted into the outer sash, allowing a pin or stop to be screwed into it with a key. The other is a one-piece lock, which is morticed into the outer sash and incorporates a bolt that can be extended or retracted, again with a key. It’s similar to the mortice security bolt, but a lot smaller.


Frame-to-Frame Lock

Sashes can also be secured with a two-piece frame-to-frame lock. One part of the lock fits on to the top rail of the inner sash, while the other part is attached to the bottom rail of the outer sash. The two are locked together with a push-in bolt or a levered bar, both of which require a key to unlock them. The disadvantage of this type of fitting is that the gap between a pair of loose fitting sashes would allow the lock to be reached from the outside. However, they are useful if fitted in combination with dual screws or lockable sash stops, especially on modern sash windows that tilt for cleaning.


Louvre windows

These windows consist of narrow blades of glass set into aluminium or plastic frames, which open and close like a Venetian blind. Over time, the blades of glass in aluminium-framed windows may become loose in their frames, and by bending the aluminium a little, a burglar can lift the glass out. While the more modern plastic types are a little more secure, the glass blades can easily be snapped in half and pulled from the frames. There is little that can be done to make a window of this type more secure, other than fitting a fixed security grille behind it.

A better option would be to replace the louvre unit with a fixed pane of 6.4mm laminated glass, using the largest possible glazing beads, which should be glued and pinned in place. Better still would be to replace it completely with a new fixed or casement window.

19. December 2010 by admin
Categories: Home Security, Windows | Tags: | Comments Off on Improve Your Window Security

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