Upgrading Door Knob Locks to Deadbolts: Is It Worth It?

The core weakness of a door knob lock is structural. The latch bolt — the spring-loaded, angled piece that clicks into the strike plate — can often be pushed back with relatively minimal lateral force or credit-card shimming because it is not a true dead latch. It is designed for convenience, not resistance. A determined intruder does not need exotic skill or tools; the same basic vulnerabilities that prompt locksmiths to field "how to pick a door knob lock" searches every month are the ones that make these locks a poor standalone solution. A double lock door knob, which adds a secondary mechanism to the knob itself, improves things somewhat, but it still does not change the fundamental geometry of a spring latch. For bedroom privacy inside a home, a door knob with lock for bedroom use is perfectly reasonable — but for an exterior entry door facing a hallway, stairwell, or street, it simply should not be your only layer.

A deadbolt, by contrast, uses a solid metal bolt that extends fully into the door frame only when you manually turn the key or thumb-turn. There is no spring to defeat. There is no give. Paired with a reinforced strike plate and longer anchor screws — ideally three inches or more to reach the wall stud behind the frame — a properly installed deadbolt raises the effort required to force entry dramatically. And a mortise lock takes that a step further still.

If you walk through a pre-war building on the Upper West Side or browse the original hardware in a landmarked Greenwich Village townhouse, you will likely find mortise locks. A mortise lock is a complete lockset that installs inside a pocket (the mortise) cut into the door's edge, housing both a deadbolt and a latch bolt in a single, robust metal case. Because the entire mechanism is embedded within the door rather than surface-mounted, it is exceptionally resistant to kick-in and prying. Many New York City multifamily buildings — especially those built before the 1970s — were constructed with mortise locks as the standard, and for good reason. They are built to handle decades of high-traffic use in the kind of dense residential environment that defines city living.

Replacing a failed mortise lock, or upgrading an older unit to a modern high-security version, is a core service our team performs throughout the New York area. Hardware brands like Schlage and Kwikset both produce quality mortise-compatible cylinders for residential and light commercial applications, and our experienced locksmiths can help you choose the right fit for your door prep and your security goals. If your door already has a mortise pocket, the upgrade path is often cleaner and faster than you might expect. Call 646-722-6780 and one of our skilled professionals will walk you through the options before any work begins.

New York City has some of the most tenant-friendly housing law in the country, and that extends to locks. Under New York City Administrative Code Section 27-2043, landlords of multiple dwellings are generally required to provide and maintain proper door locks, and tenants in most buildings have the right to install a second lock on their apartment door — typically a deadbolt — as long as they provide the landlord with a duplicate key upon request. This right is particularly relevant for tenants who discover that their existing door knob with lock is the only hardware on the door. You are not obligated to accept that as sufficient security.

That said, lease language varies, and some co-op or condo buildings have house rules that restrict which lock types or hardware brands are permitted, especially if the building has a master-key system. Before you swap out a lock cylinder or add a deadbolt, review your lease and, if needed, send a written notice to your landlord or managing agent. In buildings with a doorman or a live-in super, there may also be building-wide keying requirements. A qualified locksmith can install a deadbolt that satisfies both your security needs and your building's keying scheme — including landlord-accessible cylinders where required.

How much does an NYC locksmith cost for a deadbolt or mortise lock upgrade? It is a fair question, and the honest answer is that no responsible locksmith quotes a flat number without knowing the specifics of the job. The factors that shape the final price include the type and brand of lock hardware you choose, whether the door already has a prepared mortise pocket or requires new bore work, the time of day (emergency locksmith calls outside standard hours carry different labor considerations), and the travel distance to your location within the New York area. How much is the average locksmith charge? It varies — and any company that gives you a firm price over the phone before seeing the door should raise a flag.

What we commit to at East Coast Locksmith and Access Control is a confirmed, exact price before any work starts. You will know the full amount before our technician touches your door. There are no surprise fees added after the job is done. If you are wondering how much does a locksmith pay in New York City in terms of overhead — our mobile model means we carry the tools and hardware to you, which keeps things efficient and straightforward. For a clear, honest quote on a deadbolt or mortise lock installation, call 646-722-6780. We answer every call, every hour.

The right answer depends on your door, your building, and your goals. For a standard residential door with a cylindrical bore — the typical 2-1/8 inch hole — a single-cylinder deadbolt is the most common and practical upgrade. Installed above the existing door knob lock, it adds a true locking bolt with no spring to defeat. For doors that already have a mortise pocket, upgrading or repairing the mortise lock mechanism is almost always the better investment because you gain both a deadbolt and a latch function in one hardened unit. For commercial properties — storefronts, offices, and multi-tenant buildings — a commercial locksmith assessment is often warranted, as high-cycle hardware, master key systems, and access control integration all become relevant considerations.

A few practical things to check before calling: test whether your current strike plate screws are short wood screws (a very common weakness) or longer screws that actually reach the stud. Look at whether the door frame itself shows any previous damage, splintering, or soft wood near the strike — these are signs of a frame that will not hold even a good lock under force and may need reinforcement. Note whether your door swings in or out, because outswing doors require different hinge and lock security considerations. Our experienced team handles all of these scenarios daily, from single-family homes in Queens to high-rise apartments in Midtown, and we bring the right hardware for the job on the first visit.

East Coast Locksmith and Access Control handles a wide range of residential, commercial, and automotive needs across the New York area. Our services include: residential deadbolt installation and replacement, mortise lock repair and replacement, door knob lock rekeying, lock cylinder replacement, master key system setup for multifamily buildings, high-security lock upgrades, access control system installation, keypad and smart lock installation, mailbox lock replacement, intercom and buzzer system integration, storefront door lock installation, commercial mortise lock service, panic bar and exit device installation, door reinforcement and strike plate upgrade, window lock installation, garage door lock service, car lockout response, motorcycle lockout service, truck lockout response, transponder key programming, car key cutting and duplication, ignition repair and replacement, broken key extraction (door and ignition), safe opening and combination change, padlock replacement and installation, re-keying after a move or tenant change, emergency lockout response for homes and businesses, building-wide rekeying projects, and lock upgrades following a break-in or attempted forced entry. If your specific need is not listed, call us — if it involves a lock, a key, or access control, we almost certainly handle it.