Deadbolts: The Residential Security Standard
The deadbolt is the workhorse of residential and light commercial security: a bolt that must be manually thrown and retracted — not spring-latched — so it cannot be slipped with a credit card. Installed above or instead of a knob latch, deadbolts resist kick-in force when paired with solid doors, long screws, and proper strike plates.
Most North American homes use single-cylinder deadbolts (key outside, thumb turn inside). Double-cylinder models require a key on both sides, common near glass panels. Grade 1 ANSI/BHMA deadbolts survive more cycles and impact than Grade 3 hardware — a distinction buyers often overlook.
Single vs. Double Cylinder
Single-cylinder deadbolts allow fast egress during fires — the primary reason building codes often prohibit double cylinders on main exits. Double cylinders prevent intruders from breaking glass and reaching the thumb turn, but trap risk must be weighed with local code and occupancy type.
Throw Length and Reinforcement
A one-inch bolt throw into a wood stud matters more than lock brand alone. Strike plates should use 3-inch screws into framing, not just trim. Box strikes and door jamb reinforcement kits spread kick force across the frame.
Grades and Standards
ANSI/BHMA Grade 1 deadbolts endure 800,000 cycles and heavier hammer blows than Grade 3. Look for UL 437 or equivalent when high-security cylinders are specified. Euro-profile doors use different standards — see our euro cylinder article.
Common Attack Methods
Lock bumping, picking, and drilling target the cylinder, not the bolt. Anti-drill pins, security pins, and hardened inserts address cylinder threats; heavy-duty bolts address physical force. Smart deadbolts add motor drives but should retain quality mechanical cores.
Locksmith Practice
Installing deadbolts demands accurate boring (2-1/8" cross bore, 1" edge bore), plumb alignment, and depth matching door thickness. Rekeying after move-in is standard advice — cheaper than replacing the entire lock when the hardware is sound.