Door knob replacement is a standard hardware swap that takes 20 to 40 minutes per door. The job has been simplified by Canadian and US standardization — every modern interior door uses the same 2-1/8 inch face-bore hole, 1 inch edge-bore hole, and 2-3/8 inch backset (distance from door edge to centre of bore). New knobs from any major brand (Schlage, Kwikset, Defiant, Weiser) drop into existing prep without modifications.
This guide covers passage knobs (no lock), privacy knobs (push-button lock for bathrooms and bedrooms), and keyed entry knobs (front door). Deadbolts are similar but not identical — covered in a separate guide.
Before you start
Three things to settle:
1. Knob type matches function. Passage = no lock (closets, hallways). Privacy = push-button or thumb-turn lock with emergency unlock from outside (bathrooms, bedrooms). Keyed entry = exterior keyed lock (front and back doors). Don't put a passage knob where you need privacy, and don't put privacy where you need keyed entry.
2. Bore standard sizes. Modern doors: 2-1/8 inch face bore, 1 inch edge bore, 2-3/8 inch backset for interior, 2-3/4 inch backset for exterior. Most replacement knobs adjust to either 2-3/8 or 2-3/4 inch backsets via a sliding latch mechanism. Older doors may have non-standard prep that requires custom hardware.
3. Same brand for matching keys. If your home has multiple keyed doors and you want them all to use the same key, buy all knobs and deadbolts from the same brand and same keyway (Schlage SC1, Kwikset KW1). Most retailers offer 'keyed-alike' bundles that match all keys to one cut.
What you'll need
Tools
- Phillips screwdriver
- Flathead screwdriver (small)
- Tape measure
- Pencil
Materials
- New door knob (matching function: passage, privacy, or keyed entry)
- Replacement screws if needed (most kits include)
Buy keyed-alike sets to avoid a key ring nightmare
If you're replacing multiple keyed locks at once, ask the retailer for keyed-alike sets — all locks ship matched to the same key cut. Schlage and Kwikset both offer this; price is the same as individual locks.
Without keyed-alike, every lock comes with its own keys and you end up with 4-6 keys for your front, back, garage, and storage doors. Worth the request before you buy.
Step-by-step instructions
Identify the screws on the existing knob
Look at the inside-side knob. Most modern knobs have two screws on the trim plate (the round backplate behind the knob) — these screws clamp the inside knob to the outside knob through the door.
Some older knobs have hidden screws — pop the trim plate off (small flathead pries it off) to reveal them.
Remove the screws
Unscrew the two trim-plate screws. The inside knob will pull off the door once both screws are out.
On the opposite side, the outside knob slides out — there's no fastener on the outside; the inside-side screws hold both knobs.
Remove the latch mechanism
Open the door and look at the door's edge. You'll see the latch mechanism (the spring-loaded angled tongue that catches the strike plate on the door frame). It's held by two screws on the door's edge.
Unscrew both. The latch mechanism slides out of the edge bore.
Set the new latch's backset (if adjustable)
Most modern latch mechanisms adjust between 2-3/8 inch backset (most interior doors) and 2-3/4 inch backset (most exterior doors).
Measure the distance from the door's edge to the centre of the face bore — this is your backset. Slide the new latch's adjustment to match.
If the latch is too short for your door's backset, return it for the longer version.
Install the new latch in the edge bore
Slide the new latch into the door's edge bore. The angled side of the latch tongue should face the direction the door swings closed (so the door pushes the latch in when closing).
Drive the two latch screws through the latch's faceplate into the door edge.
Insert the outside knob
On the outside of the door, slide the outside knob's spindle through the latch mechanism's centre hole.
The knob should sit flat against the door's outside face.
Attach the inside knob
On the inside, slide the inside knob over the spindle from the opposite direction. The two knobs should sit flat against the door, sandwiching the latch mechanism between them.
Drive the inside knob's two trim-plate screws through the door into the threaded posts on the outside knob. Tighten alternately (one screw a few turns, then the other) to keep the knobs even.
Verify operation
Turn the knob from both sides — the latch tongue should retract smoothly and spring back when released.
Close the door — the latch should engage the strike plate on the frame, holding the door closed.
Open and close the door several times to confirm smooth operation.
Adjust the strike plate if needed
If the door doesn't close smoothly or the latch doesn't engage cleanly, the strike plate on the frame may need slight adjustment.
Loosen the strike plate screws, shift the plate slightly (typically up/down or in/out), and re-tighten. The latch should drop into the strike-plate hole when the door closes.
Test lock function (privacy or keyed entry)
For privacy knobs: press the button on the inside, try the outside knob — should not turn. Insert a small flat tool (paperclip, small flathead) into the outside knob's emergency override hole; press to release the lock from outside.
For keyed entry: insert the key, turn — should turn freely. Lock and unlock from both sides. Confirm the lock engages firmly.
Common mistakes that cost you
- Wrong knob type for the function. Passage knobs in bathrooms = no privacy. Keyed knobs on bedrooms = inconvenient. Match the knob to the room's needs.
- Skipping backset measurement. If the new latch doesn't fit the door's backset, the knob doesn't function. Always measure first.
- Tightening one screw fully before the other. Twists the knob assembly. Tighten alternately, both sides snug at the same rate.
- Wrong latch orientation. If the angled side of the latch faces the wrong way, the door won't close. The angle must face the door's closing direction.
- Not testing before walking away. Knobs that don't engage the strike plate or that bind during turning need adjustment now, not after the family is locked out.
Frequently asked questions
What's the difference between passage, privacy, and keyed entry?
Passage: no lock, just turns to open the latch. Use on closets, pantries, hallways.
Privacy: push-button or thumb-turn lock from inside, emergency override from outside (small hole that accepts a paperclip). Use on bathrooms, bedrooms.
Keyed entry: keyed lock from outside, thumb-turn from inside. Use on exterior doors and any door requiring outside-only locking.
Can I rekey a lock to match my other keys?
Yes — most modern locks can be rekeyed by a locksmith for a modest per-lock fee. Some locks (Kwikset SmartKey) have user-rekeyable mechanisms; Schlage and Weiser typically need a locksmith.
Or buy keyed-alike sets at purchase for the same price as individual locks.
Why does my door not close cleanly with the new knob?
The latch tongue isn't aligning with the strike plate hole. Common causes: wrong backset on the latch, slightly different latch tongue dimensions on the new knob versus the old, or worn strike plate from previous use.
Adjust the strike plate on the frame to align with the new latch's tongue position. Loosen, shift, retighten.
Can I install a smart lock myself?
Yes — most smart deadbolts and knobs install identically to mechanical versions. The smart components add battery and electronic connections but the bore prep and installation steps are the same.
WiFi-connected smart locks need additional setup with a phone app and home network. Plan an extra 30 minutes for initial connection and key generation.
When to call us instead
If your door has non-standard prep (older home, custom door, or damaged bore holes), drilling new prep is technical work that's hard to undo. We handle door hardware replacement as part of larger renovation work.
Book a free 60-minute site visit →Related Ottawa services
If you're updating multiple doors as part of a refresh, our residential renovation team handles doors, hardware, and trim as fixed-price work. Book a free 60-minute consultation.