|
|
Doors
are vulnerable to forcing and often used by an intruded
as a quick means of exit with his haul, even if he
entered through a window. It makes good sense to fit
strong locks and bolts: don't rely on the old nightlatch,
which offers no security at all - it is only as strong
as the screws holding it to the door and a thief can
easily break a pane of glass to operate it or simply
slide back the bolt with a credit card.
Front doors and back doors need
different locking arrangements and there are various
mechanisms to choose.
The choice of door locks
The door by which you leave the house
- usually the front door - needs a particularly strong
lock because it can't be bolted top and bottom, except
at night when you're at home and a break-in is less
likely. Back and side doors need bolts top and bottom to
prevent them being smashed in from outside, plus a lock
to stop thieves making a getaway with their spoils.
The basic choice of locks is between
mortise and rim types.
| How a mortise lock works |
|
|
| |
|
|
 |
|
A mortise lock is
fitted into a slot cut in the edge of the door,
where it cannot easily be tampered with. There
are various patterns to suit the width of the
door stile ( which should be a minimum of 45mm
thick ) and the location of the door: a two-bolt
mortise is suitable for side and back doors. It
has a handle or knob on each side, to operate a
springbolt , and a key-operated deadbolt which
cant be pushed back once the door is closed.
Purely key-operated mortise locks and cylinder
mortise locks are best for final exit doors,
where no handle is necessary. It's best to use
one in tandem with a rim latch.
Choose a lock that conforms to BS3621: this
ensures that it has a minimum of 1000 key
variations, is proof against 'picking' and is
strong enough to resist drilling or forcing,
having a deadbolt of hardened steel.
Some locks are intended for
right-hand or left-hand opening doors.
|
| |
|
|
| How a cylinder rim lock works |
|
|
 |
|
A cylinder rim
lock is usually used on final exit doors as an
alternative to a mortise lock (or as an addition
for extra security): it fits on the inner face
of the door and shoots a bolt into a plate fixed
to the face or into the edge of the frame.
A rim lock automatically holds the door closed
when it is pulled shut, can be opened from
inside by a knob, but needs a key so it can be
opened from the outside. Choose a rim lock which
has a deadlockable bolt, thrown by an extra turn
of the latch key, or one that is automatically
deadlocking.
The best type has its staple fixed into the edge
of the frame with screws or a metal stud: if
it's only screwed to the face, a well-placed
kick will rip out the screws.
A more secure type of rim latch incorporates a
hook bolt, which is difficult to force open.
|
| |
|
|
|
Installing a door viewer |
|
|
 |
|
A door viewer enables you to
identify callers before admitting them. Select a
viewer with as wide an angle of vision as
possible: you should be able to see someone
standing to the side of the door or even
crouching below the viewer. Choose one that is
adjustable to fit any thickness of door.
Drill the recommended size
hole - usually 12mm diameter - right through the
centre of the door at a comfortable eye level,
insert the barrel of the viewer into the hole
from the outside, then screw on the eyepiece
from inside, using a coin to tighten it.
|
| |
|
|
| |
|
|
|
|
