Deadbolt Installation Across Mississauga

The latch in a knob or lever is spring loaded and bevelled, which is what lets the door close by pushing it. That bevel is also what lets a piece of plastic slip it. It is a convenience mechanism, not a security one.

A deadbolt has no spring and no bevel. It is a square ended bar driven by the key or the thumbturn, and once thrown it can only be retracted the same way. Nothing can slip it, and defeating it means defeating either the cylinder or the frame it sits in.

That is the whole argument for a deadbolt, and it is why a house with a handle lock alone is not really locked. It is closed.

Most residential forced entries do not defeat the lock. They defeat the jamb. Someone kicks the door and the strike plate, held by two short screws into soft pine trim, tears out with a section of the frame attached. The deadbolt is still locked, still perfect, and now lying on the floor inside a hole.

The fix is a reinforced strike, which is a longer, thicker plate with a deeper pocket, anchored with screws long enough to pass through the jamb, through the shim space, and bite into the structural stud behind it. Three inch screws are the minimum. That change alone raises the force needed to open a door by a very large margin, and it costs less than the lock does.

A box strike, which encloses the bolt on all four sides rather than presenting an open hole, adds further resistance to spreading the frame. On a front door it is worth specifying.

A single cylinder deadbolt takes a key outside and has a thumbturn inside. A double cylinder needs a key on both sides. The choice is a genuine trade off, not a matter of one being better.

Front door first, obviously, but the doors people skip are the ones that matter most in practice.

A deadbolt should throw at least one inch. Shorter bolts are common on cheap hardware, and a short bolt in a frame that is even slightly out of line barely engages, which means the door can be spread open without breaking anything.

Backset is the distance from the door edge to the centre of the bore, and it is either 2 3/8 inch or 2 3/4 inch in North America. Get this wrong and the lock will not fit the existing prep. Most quality deadbolts ship with an adjustable latch that handles both.

A hardened steel insert in the bolt is worth having, because it defeats a hacksaw attack on a door with a gap. On a door with a wide gap or an exposed bolt, a saw resistant bolt matters more than the cylinder grade does.