Disadvantages
Door chains normally come equipped with very short screws which easily rip out. Any amount of force capable of defeating a deadbolt will also defeat a door chain. The tracks are usually straight, and any number of simple tools will allow the chain to be separated from the track. Elderly individuals, uncoordinated people, and individuals with hand tremors may find it difficult to connect the chain to the track. The chain is often a thin metal. Door chains are often installed improperly, making them easily subjected to a number of attacks.
UPVC/PVCU front doors are generally unsuitable for retrofit security devices. Not only is the material not strong enough to support devices fitted with steel screws unless secured into the internal metal framework, but such changes to the original design may invalidate an existing warranty or possibly damage the integral locking assembly.
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