Can a deadbolt replace a knob lock entirely?

Not practically. A deadbolt provides the security bolt, but a knob or lever handle is still needed for the door latch — the two serve different mechanical roles. Most exterior doors in Canada are built to accept both, and running both gives you the strongest layered defence.

What grade of deadbolt should I buy for a front door?

ANSI Grade 1 is the commercial standard and the strongest available; Grade 2 is solid for most residential exterior doors. Avoid Grade 3 hardware on any exterior opening — it's rated for interior privacy use only. A qualified locksmith can tell you whether your existing hardware meets grade on the first visit.

Does door alignment affect how well a deadbolt works?

Yes. A bolt that can't fully extend into the strike plate — because the door sags, swells, or is out of square — provides a fraction of its rated strength. Poor alignment is one of the most common reasons a 'good' deadbolt still fails under forced entry.

Residential Security Updated June 27, 2026

Deadbolt vs. Knob Lock: Why You Need Both for Real Security

By Treco Locksmith & Security · rated 5★ across 205 Google reviews · serving Burlington & Hamilton

Most homeowners focus on the handle they touch every day — the knob or lever — and treat the deadbolt as an afterthought. In practice, the opposite priority makes more sense. Understanding what each lock actually does (and where it fails) is the quickest path to a front door that holds up when it matters.

What a Door Knob Lock Actually Does

A knob lock is a spring-latch mechanism built into the handle. The latch retracts automatically when you turn the knob, which is exactly what makes it convenient — and what makes it weak.

Spring latches can be slipped with a credit card or thin shim in seconds. They’re also vulnerable to torque attacks: grip the knob hard and apply rotational force, and many will yield without picking. Building codes classify knob locks as passage or privacy hardware, not security hardware.

That’s not a flaw — it’s by design. Knob locks are meant to keep a door closed and latched, not to resist a forced entry attempt.

What a Deadbolt Actually Does

A deadbolt throws a solid steel bolt — typically 1 inch — into the door frame with a full turn of the thumb-turn or key. There is no spring; the bolt does not retract from pressure or torque alone. To open it, you need the key or you need to destroy the door.

Single-cylinder deadbolts (keyed outside, thumb-turn inside) are the standard choice for most exterior residential doors. Double-cylinder models require a key on both sides, which has fire-egress implications — discuss the trade-offs with your locksmith before choosing one.

The strength of a deadbolt is not just the bolt itself. It depends on:

Strike plate and screws. A standard strike plate with short screws can be kicked in regardless of bolt quality. A reinforced strike plate with 3-inch screws into the stud is the actual barrier.
Door and frame condition. A solid-core door and an intact frame are prerequisites. A deadbolt in a hollow-core door or a rotted frame offers minimal resistance.
Bolt engagement. The bolt must fully extend into the strike plate opening. If the door is out of alignment — sagging, swelling, or racked — the bolt may only partially engage. See our post on why door alignment matters more than you think for more on this.

Why You Need Both

The knob lock handles day-to-day convenience: the latch catches when you pull the door shut. The deadbolt handles security: it provides the bolt that resists forced entry.

Running only a deadbolt means the door isn’t truly latched unless you manually lock it every time — a habit most households won’t sustain. Running only a knob lock means the door is latched but one quick technique away from being opened by anyone.

Together, they create layered protection without any trade-off in convenience. This is why virtually every residential exterior door in Canada is built with both a knob/lever prep and a deadbolt prep.

Choosing the Right Deadbolt

Not all deadbolts are equal. ANSI grading gives a useful baseline:

Grade 1 — commercial-grade, highest impact and cycle ratings; appropriate for any exterior residential door and recommended for high-traffic or higher-risk properties
Grade 2 — solid residential choice; meets most building requirements
Grade 3 — interior and privacy use only; should never appear on an exterior door

Look for brands with proven field reliability. Our breakdown of lock brands worth trusting covers what to look for and what to avoid.

If you’re renting or have recently moved, rekeying both locks at the same time is typically the first step — not purchasing new hardware. Rekeying is faster, costs less, and leaves you with a fresh key profile that only you hold.

Installation and Professional Fit

A deadbolt installed poorly performs worse than one that’s never been upgraded. Common DIY mistakes include under-driven strike plate screws, misaligned bolt and strike, and inadequate bore depth. Each of these reduces the rated resistance of the hardware significantly.

A professional installation ensures the bolt extends fully, the strike plate is backed by structural screws, the hardware operates without binding, and the door itself is aligned correctly before the lock goes in. Our residential locksmith services in Burlington and the surrounding Halton area cover new installs, upgrades, and rekeying — typically in a single visit.

A Note on Lock Brands

Grade and installation aside, hardware quality matters. Treco works with reputable Canadian brands — Weiser, Schlage, Medeco, and others — and can source Grade 1 deadbolts that balance cost, performance, and long-term durability for the climate conditions typical in Burlington and the broader Halton region.

If you’re unsure what’s currently on your door or whether it meets grade, a quick assessment during any service call can answer that without adding cost.

deadboltsrekeyingburlingtonhigh-security