How to Swap Knobs for Levers Across a House

Why this matters

A round knob asks for a tight grip and a twist of the wrist at the same time, and for a customer with arthritis, a weak grip after a stroke, or one hand busy on a cane, that combination is exactly what they no longer have. They stop closing the bathroom door. They leave the front door unlocked because the deadbolt is the second hard thing. Swapping every knob for a lever is one of the cheapest modifications in this category and one of the few a person notices on the first day.

It is also a job that goes sideways in small ways: a latch that will not catch a strike set for the old hardware, a lever that hits the wall when the door swings open, a bathroom lock with no way in from outside if the person falls. All of it is caught at survey time, not at install time. Why a lever works for a hand that a knob does not is owned by a sibling: see related, Lever Handles and Controls a Hand Can Work. This is the house-wide procedure.

Step 1: Survey every door before you order anything

Walk the house with a tape, a notepad and the person, and fill in one line per door. Doing the whole house on one sheet is the point: hardware comes in sets, and a single missed door with an odd backset or a mortise lock means a second trip and a mismatched door.

For each door, record:

• Function. Passage (no lock), privacy (push-button or turn lock, with an outside emergency release), keyed entry, or dummy (fixed lever, no latch, for a closet with a ball catch).
• Backset. The distance from the edge of the door to the center of the big cross bore. Residential doors are almost always 2-3/8 or 2-3/4 inches. Most residential latches adjust between the two; confirm the one you buy does.
• Bore. The cross bore is commonly 2-1/8 inches in diameter, the size ANSI/BHMA A156.2 bored locks are built around; the edge bore for the latch is commonly 1 inch. An older door bored for a smaller or a non-standard knob is the one that needs drilling.
• Latch faceplate. Round drive-in (no mortise in the edge), radius corner or square corner. The new latch has to match what is cut, or the edge gets chiseled.
• Door thickness. Interior doors are usually 1-3/8 inches, exterior 1-3/4. Lever sets list the thickness range they fit.
• Clearance. Open the door fully and look at what the handle hits. A knob that clears a wall by an inch is replaced by a lever that projects farther and dents the drywall on the first swing.
• Mortise lock. In an older house, a tall rectangular lockbox set into the door edge, not a round bore. Bored lever sets will not fit it.

What breaks if you skip it: you open the boxes on site and find the one pantry door with a drive-in latch, or the bedroom door with a mortise lock, and the job finishes with one knob left in the house.

Step 2: Read the egress door before you touch its hardware

The door the person leaves by in a fire is the one where the hardware decision has a code behind it. The IRC requires the egress door to be readily openable from inside without a key, special knowledge or effort (R311.2, as adopted by your jurisdiction).

That rules out one thing you will find more often than you expect: a double-cylinder deadbolt, keyed on both sides. Someone installed it so a burglar could not reach through a sidelight. Inside, it means the person has to find the key in the dark while the house fills with smoke. Replace it with a single-cylinder deadbolt with a thumbturn inside.

Then make the thumbturn usable. A small thumbturn is a pinch and a twist, the same motion the lever was supposed to eliminate. Choose a large winged thumbturn. If two motions (deadbolt then lever) are still too many, an interconnected lockset retracts both the latch and the deadbolt with one push of the inside lever; it fits a door bored for both at the right spacing, and the survey line should note whether this one is.

Electronic and keypad entry locks are their own subject; see related, How to Set Up Smart Devices With a Disabled User.

Step 3: Pick hardware that fits the holes already in the doors

The goal is levers that drop into the existing bores with no drilling.

• Grade. ANSI/BHMA A156.2 grades bored locks for durability, with Grade 1 the heaviest. A lever acts as a lever on the latch's spring; a light-duty set with a long lever sags out of level within a year, especially on the doors used most. Grade 2 or better for anything that gets daily use.
• Return-style levers, whose ends curve back toward the door, catch fewer sleeves, bag straps and walker handles than a straight lever.
• Handing. Most residential levers are reversible; some are handed for a left- or right-swing door. Check against the survey before ordering.
• Operation. The 2010 ADA Standards describe operable parts as usable with one hand, without tight grasping, pinching or twisting of the wrist, at no more than 5 pounds of force (309.4), and door hardware between 34 and 48 inches above the floor (404.2.7). In a private home those are a reference, not a requirement, and a useful one to hold the hardware to.

Pocket doors are the exception to this whole article. There is no lever that works on a pocket door; the options are an edge pull large enough for a fist, a loop pull, or a different door.

Step 4: Handle the strikes

The strike is the plate on the frame that the latch snaps into. Old strikes were set for old latches, and two things go wrong when the latch changes:

• The latch misses. The new latch sits slightly higher or lower, or projects differently, and the door no longer catches. Close the door slowly and watch where the latch tongue meets the strike. If it lands on the plate rather than the opening, file the opening or move the strike.
• The lip is too short. The curved lip on the strike guides the latch in. A short lip on a door that a person pushes closed with an elbow or a hip, rather than pulling with a hand, lets the latch bounce off. Fit a strike with a longer lip.

Weatherstripping on the entry door compresses as the door closes. A latch that only catches when you lean on the door will not catch when the person lets it swing. Test it with the door released, not pushed.

Hazard: chiseling a strike mortise or a latch faceplate means a sharp chisel driven toward your own hand on a door that moves. Wedge the door so it cannot swing, keep both hands behind the cutting edge, and wear eye protection; old painted frames in a pre-1978 house shed lead-painted chips when chiseled, so lay a drop cloth and clean up with a HEPA vacuum, not a broom.

Step 5: Install in a sequence that never leaves a door unusable

Do the doors one at a time, start to finish, so no bathroom or exit is ever without working hardware.

1. Remove the knob, latch and strike.
2. Fit the new latch, checking it is set to the backset you recorded.
3. Fit the lever set, with the lever pointing the way the survey said it should for that swing.
4. Fit or adjust the strike.
5. Close and latch the door three times by releasing it, not pushing it.
6. For a privacy set, lock it from inside, close it, and open it from outside with the emergency release, then show the household where the release key is kept. A person who falls in a locked bathroom is reached through that release, or through a broken door.

Leave the egress door for last so the person can see the deadbolt change and practice it while you are still there.

Worked example: a one-story house with eleven doors

The customer has rheumatoid arthritis in both hands. She cannot turn the bathroom knob when her hands are bad and has started leaving it open. The survey:

DOOR        FUNCTION  BACKSET  FACEPLATE  NOTE
Front       keyed     2-3/4    square     double-cyl bolt
Garage      keyed     2-3/8    square
Bath main   privacy   2-3/8    radius     lever hits towel
                                          bar, add stop
Bath hall   privacy   2-3/8    radius
Bed 1       passage   2-3/8    radius
Bed 2       passage   2-3/8    radius     strike: latch
                                          lands on plate
Bed 3       passage   2-3/8    radius
Linen       passage   2-3/8    radius
Hall closet passage   2-3/8    radius
Pantry      passage   2-3/4    drive-in   round edge bore
Basement    passage   2-3/8    radius

Eleven doors: two keyed, two privacy, seven passage. Nine at 2-3/8 inch backset and two at 2-3/4. The sets ordered have latches adjustable between the two, so backset is not a problem anywhere; the survey still recorded it, because it decides which way each adjustable latch is set.

The four lines with a note are the job.

• Front door: the double-cylinder deadbolt comes out. A single-cylinder deadbolt with a large winged thumbturn goes in. She tried it with a closed fist in front of the tech and could turn it; she could not turn the old small one.
• Bath main: the longer lever would strike a towel bar 2 inches beyond where the knob stopped. A hinge-pin door stop limits the swing so the lever stops short of the bar. Moving the bar was the alternative, and she wanted the bar where it was.
• Bed 2: with the new latch fitted, the tongue landed 1/8 inch high on the strike plate. The strike opening was filed 1/8 inch upward and the door then latched on release three times.
• Pantry: a drive-in round latch fits the round edge bore without chiseling. Ordering a standard radius latch for it would have meant cutting the door edge on a door that did not need it.

Testing with her. On every door she pushed the lever down with a closed fist and then with her forearm, the way she does on a bad day. Every passage and privacy lever worked both ways. The privacy button on the hall bath was too small to press with a fist, so that set was swapped for one with a turn-lever privacy lock she could operate with the side of her hand. The emergency release key went on a hook outside each bathroom door, at her request, rather than in a drawer.

Job time ran close to the estimate. The one thing the survey had not caught was the privacy button, and it was caught only because she tried it herself.

How to verify you got this right

Every door latches when released from half-open, not only when pushed. Every privacy lock opens from outside with its release. The egress door opens from inside with one motion she can do with a closed fist. And she has worked every handle herself before you leave, on the hand she uses on her worst day, not her best.

References

• IRC Section R311.2 (egress door), as adopted by your jurisdiction.
• ANSI/BHMA A156.2, bored and preassembled locks and latches, through the product's grade listing.
• 2010 ADA Standards for Accessible Design, 309.4 and 404.2.7, used as a dimensional reference only in a private home.
• See related: Lever Handles and Controls a Hand Can Work; How to Set Up Smart Devices With a Disabled User; The Levers Nobody Asked For.