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The lock is not what fails. The frame is.
Almost every forced residential door we are called to had a perfectly good deadbolt in it. What gave way was two short screws in a softwood jamb.
What a deadbolt installation should include
- A bolt with a one inch throw. California asks for thirteen-sixteenths of an inch on a rental's main entry. Several cities here ask for a full inch. The difference costs nothing and it is the part of the lock that actually resists anything.
- A reinforced strike plate. Not the thin pressed plate that came in the box. Heavy gauge, with a deeper pocket.
- Screws that reach the stud. Two and a half inches minimum, through the jamb and into the framing behind it. This single item does more for your door than the lock does.
- Solid backing at the strike. Where the gap between the trimmer and the jamb is hollow, it gets shimmed solid first. Otherwise long screws just pull a hollow box out of the wall in one piece.
- A bolt that sits properly in its pocket. If you have to lift or lean on the door to throw the bolt, it is not fully home, and a bolt that is not fully home is not doing its job.
What the local codes ask for
The state baseline for rentals is Civil Code 1941.3: a deadbolt with a throw of at least thirteen-sixteenths of an inch on the main entry. Subdivision (f) switches that duty off for a building designated as a historical structure, which matters in San Francisco and in Palo Alto.
Several cities go further and write their own numbers. South San Francisco and San Mateo both ask for a one inch throw, solid core doors, two and a half inch strike screws and a 16 gauge deadbolt strike plate. Fremont asks for a one inch throw with a cylinder guard and a hardened steel insert on new work. Pacifica has required a deadbolt in addition to the latch since 1988.
We fit to the higher standard everywhere, because the cost difference is a few dollars and the failure mode is your front door.
California Civil Code §1941.3; SSFMC ch. 15.48; San Mateo Municipal Code ch. 23.54; Fremont Municipal Code ch. 15.50; Pacifica Municipal Code ch. 5-27.
Words you will hear
Single or double cylinder, and why we will usually say single
A double cylinder deadbolt needs a key on the inside as well as the outside. People fit them where there is glass beside the door, so that breaking the glass does not let somebody reach in and turn the thumbturn.
The problem is the other direction. In a fire, at night, in smoke, you cannot leave your own house without finding a key. Pacifica wrote the prohibition into its municipal code in 1988: "Double-keyed, double-cylinder deadbolts are not permitted."
If glass near the door is your worry, the answers are laminated or burglary-resistant glazing, a thumbturn that cannot be reached from the opening, or moving the bolt. Not a second keyhole.
On a door that is already damaged
If the frame has been forced before, a new deadbolt on its own fixes nothing. A split jamb opens to a shoulder regardless of what cylinder is in it.
The repair is the jamb: new material where it split, solid blocking behind the strike, and then the hardware. We will tell you if the door itself is past saving rather than fitting good hardware to something that will not hold it.
Questions
Can you fit one to a door that has never had a deadbolt?
Yes. It needs a bore through the door and a pocket in the frame, which is normal work. On a very old or unusual door send a photo of the door edge first.
I bought a lock already. Will you fit it?
Yes, once we have checked it suits your door. Thickness, backset and bore size all have to match, and a smart lock in particular can arrive wrong for an old door.
How long does it take?
A straightforward deadbolt on a prepared door is under half an hour. A new bore plus frame work takes longer, and we will say so before starting.
Will one key work for all my doors?
Yes, if the locks share a keyway. We key them alike while we are fitting them, at no meaningful extra cost.
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