Deadbolts

Unlike the spring-latch on a doorknob, which can often be bypassed with a credit card or forced back under pressure, a deadbolt uses a solid steel bolt that must be intentionally extended deep into the doorframe by the turn of a key or thumb turn. This bolt cannot be moved to the open position except by rotating the lock cylinder. This simple, powerful mechanism is the cornerstone of your security. As of Wednesday, September 10, 2025, understanding the different types of deadbolts and the professional standards that govern them is key to choosing the right protection for your Los Angeles home.

The Three Main Types of Deadbolts

Deadbolts come in three primary varieties. Choosing the right one depends on your door’s construction, its location, and your family’s safety and security priorities.

1. Single-Cylinder Deadbolts

This is the most common type found in American homes and likely the one you are most familiar with. It features a key cylinder on the exterior and a simple, ergonomic thumbturn on the interior to lock or unlock the bolt.

• Pros: Its primary advantage is convenience and safety. The thumb turn allows for a quick, keyless exit in an emergency, which is a critical feature for any primary exit door. It’s simple, intuitive, and easy for all family members to operate.
• Best For: Solid wood, metal, or fiberglass doors that do not have any adjacent glass panels through which an intruder could reach the interior thumb turn.

2. Double-Cylinder Deadbolts

To solve the “smash and reach” vulnerability of single-cylinder locks, a double-cylinder deadbolt removes the thumbturn entirely, requiring a key to lock or unlock the door from both the inside and the outside.

• Pros: This design offers maximum security for doors with glass panels. Even if the glass is broken, the deadbolt cannot be unlocked from the inside without the correct key, rendering the entry point useless to an intruder.
• Cons & CRITICAL SAFETY WARNING: This design can pose a significant life safety risk in an emergency like a fire. In a panicked situation, needing to locate a key to escape a locked door can have tragic consequences. For this reason, double-cylinder deadbolts are often against California fire code for residential egress doors. They should never be used on a primary entrance or exit.
• Best For: Very specific, limited applications. A double-cylinder lock might be considered for a secondary, non-primary exit door, such as a workshop or garage door that has glass, provided there are multiple other clear and accessible emergency exits from the building. We at Guardian Angel Lock & Security strongly recommend a professional consultation before even considering this option to ensure you are not compromising your family’s safety.

3. Captive Thumb turn (or Hybrid) Deadbolts

Offering the best of both worlds, this innovative design provides the flexibility of a single-cylinder lock and the high security of a double-cylinder lock, solving the classic “security vs. safety” dilemma.

• Pros: This is the ultimate solution for flexibility and peace of mind. You get safe egress when you need it and heightened security when you want it.
• Best For: Virtually any application, but it is the premier, safest high-security solution for homes with decorative glass near the entryway. Products like the Mul-T-Lock Hercular® Captive Deadbolt are a perfect example of this advanced technology.

Beyond the Basics: What a Professional Considers

At Guardian Angel Lock & Security, our analysis goes far beyond just the type of deadbolt. A lock’s true strength is a combination of its construction, its cylinder, and its installation.

Security Grades (ANSI/BHMA)

We supply and install deadbolts that meet the two highest industry standards for strength and durability.

• Grade 2: A heavy-duty residential and light commercial rating. A Grade 2 lock is a significant security upgrade over the basic “Grade 3” hardware found in big-box stores.
• Grade 1: The highest possible rating, certified for heavy commercial use. These locks are built to withstand the most extreme forms of forced entry and are the top choice for ultimate security.

The Cylinder: The Brain of the Lock

The real security of a deadbolt lies not in its body, but in its cylinder—the component the key operates. Most standard residences are equipped with brands like Schlage® or Kwikset®. While they produce solid deadbolts, even their higher-grade offerings often come with standard, non-high-security cylinders vulnerable to picking, drilling, and “bumping” (a fast, low-skill attack using a special key).

We can upgrade any deadbolt we sell with a high-security, UL437-listed cylinder from elite brands like MUL-T-LOCK. This upgrade provides:

• Pick and Drill Resistance: Complex, telescoping pin systems and hardened steel components that make manipulation nearly impossible.

 

• Patented Key Control: This is a critical feature. Your lock comes with a unique key order card. No one can make a copy of your key without that card, preventing unauthorized duplication by contractors, valets, or anyone who temporarily has your key.

Proper Installation: Anchoring Your Security

A Grade 1 deadbolt is only as strong as its installation. A DIY job or an installation by a general handyman often overlooks the most critical component: the door frame.

• The Bolt: We ensure every lock has a bolt that extends a minimum of one full inch—the industry standard “throw”—deep into the door frame.
• The Strike Plate: The standard strike plate that comes with most locks is a thin piece of metal secured by short screws into the soft wood of the door jamb. This is the weakest point. Our professional installation includes a heavy-gauge, high-security strike plate anchored with 3-inch long construction screws that bypass the weak jamb and bite directly into the solid stud framing of your house. This step alone can increase kick-in resistance by several hundred percent.

The right deadbolt for your home depends on your door’s style, your family’s needs, and your desired level of security. Contact our experts at Guardian Angel Lock & Security today for a comprehensive consultation to find the perfect solution to keep your Los Angeles home safe.

Learn more about our Residential Products here:

• Closed-Circuit Television (CCTV)
• High Security Locks-MT5+
• Mul-T-Lock 800 High Security 
• Mul-T-Lock Grade 1 Deadbolt 
• Intercom Systems
• Safes
• Rekeying/Cylinder Combination Change
• Card Access Control Systems/Keyless Entry
• Smart Locks
• Keys Duplication
• DoorBird
• DoorKing
• Access Control