In short:
- On an old timber door, the door and frame cause as many lock problems as the lock does. Test the lock with the door open before deciding it's worn out.
- Original rim locks and simple lever locks have character, but they were never meant for high security. Keeping them for looks and adding a modern lock for security is a common middle path.
- A new lock doesn't always fit an old pocket. Measure, or have it measured, before buying anything.
- If the house is older than 60 years, the National Heritage Resources Act's permit rule may apply to alterations. Check with the provincial heritage authority before changing visible original features.
Old houses in Joburg's older suburbs
Some of Johannesburg's suburbs are almost as old as the city. Parktown was laid out by the Randlords in the 1890s and is known for its Victorian and Edwardian homes. Melville was proclaimed in 1896. Houghton was developed around the turn of the twentieth century, and as well as large houses on big stands it has some art deco blocks of flats. Not every home in these areas is old, and many have been renovated more than once, but plenty of front doors, back doors and internal doors are a long way from new.
That matters for locks in three ways. The lock may be a type that's rarely fitted today. The door it sits in has had decades to swell, shrink, sag and collect paint. And the house itself may be covered by heritage law, which affects what you can change.
The locks you're likely to find
| Lock | How to recognise it | Typical trouble | Usual options |
|---|---|---|---|
| Rim lock (box lock) | A metal box screwed to the inside face of the door, with a keeper box on the frame | Loose screws in old timber; keeper box knocked out of line; worn spring | Re-fix and adjust; keep for looks and add a modern lock for security |
| Older lever mortice lock | Lock hidden in the door edge, long bit-style key, small faceplate on the edge | Worn levers or key; bolt rubbing on a painted-over keeper; broken spring | Repair if parts allow; replace the lock body if the pocket size suits a modern one |
| Nightlatch added later | A cylinder on the outside, a box with a small knob on the inside | Latch not catching because the door has moved | Adjust the keeper; replace the latch or cylinder if worn |
| Simple internal-door lock | Small lever key, often the same key fits several doors | Lost keys; seized from disuse | Usually a straightforward replacement |
Wikipedia's entry on rim locks describes them as the oldest type of lock used in the UK and Ireland, which explains why they turn up on houses built in that tradition. It also notes they are "not used where high security is required". Mortice locks, by contrast, sit in a pocket cut into the door edge and have traditionally used lever mechanisms; the pocket weakens a timber door somewhat, but the lock itself is better protected.
Is it the lock, or is it the door?
Old timber doors move. Hinges wear, screws lose their grip in holes that have been re-used for decades, frames settle and doors take up moisture in wet weather and dry out again. When that happens, the bolt or latch no longer meets the keeper square-on, and the lock gets blamed.
A simple test tells you a lot. With the door open, turn the key. If the bolt moves smoothly, the lock is probably healthy and the door or keeper needs attention. If it's stiff with the door open too, the lock itself is worn, dirty or damaged. Other clues that point to the door: you have to lift or push the door to lock it, it locks easily in winter but not after rain, or the bolt has worn a bright patch on one edge of the keeper. Our guide to a door that won't latch goes further into alignment problems.
Keep, repair or replace?
There's no single right answer for an old door. It depends on what the lock protects and how much the original hardware means to you.
- Keep and repair when the lock is on an internal door, still works with the door open, and is part of the house's character. Re-fixing loose screws into sound timber, adjusting the keeper and freeing a sticky bolt often brings it back.
- Keep for looks, add for security on an outside door where you love the old rim lock or handle set. The original stays; a modern lock does the real work.
- Replace the lock body when parts are broken or no longer made. ASSA ABLOY's guidance on its Union range is that 2- and 3-lever locks suit internal doors and 4- and 5-lever locks suit external doors. Union's South African range also lists sashlock variants made for glazed "cottage pane" doors, which is useful on older doors with narrow timber around the glass.
- Replace door and lock only when the timber around the lock is split or rotten and can't hold a lock securely, whatever lock you choose.
Before you buy anything, remember that an old mortice pocket may not match a modern lock's case size or backset. A lock that doesn't fit means extra cutting or filling of the door, so measure first, or have a technician measure. Lever counts and cylinder types are explained more broadly elsewhere on the blog, but on an old door, the fit and the condition of the timber matter as much as the lock you pick.
Heritage homes and the 60-year rule
Section 34(1) of the National Heritage Resources Act says: "No person may alter or demolish any structure or part of a structure which is older than 60 years without a permit issued by the relevant provincial heritage resources authority." In Gauteng, the Johannesburg Heritage Foundation's householder guide names that body as the Provincial Heritage Resources Authority (Gauteng), or PHRAG.
The Act's definition of "alter" is broad: "any action affecting the structure, appearance or physical properties of a place or object, whether by way of structural or other works, by painting, plastering or other decoration or any other means". The same guide points out that not every property over 60 years old is a heritage property, and that each is assessed on its merits.
Whether swapping a lock or handle on a particular old door needs a permit isn't something a locksmith can decide for you. If your house was built more than 60 years ago and you're planning to remove or change visible original features such as door furniture, ask PHRAG or a heritage practitioner first. Like-for-like repairs that leave the original in place are the least likely to raise questions.
What makes old locks worse
- Forcing the key. Old keys are often worn thin. A snapped bit key inside an antique lock is a slow job to remove.
- Driving longer screws into rotten wood. It holds for a week. Sound timber, or a proper repair to the door, is what holds a keeper.
- Planing the door edge without checking the hinges. If the door has dropped, tightening the hinges may fix it; planing takes away timber you can't put back.
- Painting over the lock or keeper. Paint builds up in the keeper and on the bolt and slowly stops the door locking.
- Squirting oil into the keyhole. Oil collects dust and gums up old lever mechanisms. If you don't know the lock's maker or its care instructions, leave lubrication to a technician.
- Pulling out the old lock before knowing what will replace it. You may end up with a hole nothing fits.
Getting an older lock looked at
When you contact us, these help the technician understand the job before arriving:
- A photo of each face of the lock, and of the door edge with the door open
- A photo of the key, next to a ruler if you have one
- Any maker's name or numbers on the faceplate or lock case
- Whether the door is internal or external, and whether there's a security gate in front of it
- Whether you want to keep the original hardware, and whether the house is a heritage property
We offer lock replacement and lock repair across Johannesburg, from the older suburbs north of the CBD to Bedfordview and Edenvale. It's an R250 call-out; the technician quotes on site before any work starts, and nothing is done until you agree. Payment is by EFT, cash or card. If you're weighing up a digital lock for a front door instead, read what to know about smart and keypad locks first.
Questions
Can you make a copy of my old key?
No. We don't cut or duplicate keys, and there's no shop or counter. If you're down to one key for an old lock, it can be worth replacing the lock body so you have a full set of keys from the maker.
Will a modern lock fit in my old door?
Sometimes, but not always. Older mortice pockets can be a different size and depth from today's locks. A technician measures the pocket, backset and door thickness before recommending anything, and the quote is given on site before work starts.
How do I know if my house is a heritage property?
Age alone doesn't make it one, but buildings older than 60 years have general protection under the National Heritage Resources Act. The Johannesburg Heritage Foundation and the provincial heritage authority (PHRAG) are the people to ask.
Need a locksmith to look at it?
If this hasn't solved the problem, our lock replacement service covers it. We're a mobile locksmith in Johannesburg, so we come to your door. Areas where this comes up often include Parktown, Houghton, Melville.
Sources and further reading
- National Heritage Resources Act 25 of 1999, section 34: Structures (Acts Online) — the 60-year permit rule for altering structures
- Johannesburg Heritage Foundation: Heritage Hints for Homeowners and Developers (PDF) — PHRAG as Gauteng's authority, the Act's definition of 'alter', not every 60-year-old property is a heritage property
- Wikipedia: Parktown — established by the Randlords in the 1890s; Victorian and Edwardian homes
- Wikipedia: Melville, Gauteng — proclaimed in 1896
- Wikipedia: Houghton Estate — developed around the turn of the twentieth century; large houses and art deco flats
- Wikipedia: Rim lock — surface-mounted locks, their history and limited security
- Wikipedia: Mortise lock — the mortice pocket, lever mechanisms and effect on timber doors
- ASSA ABLOY: Mortice locks and conversion sets — 2- and 3-lever for internal doors, 4- and 5-lever for external doors
- ASSA ABLOY South Africa: Union sash locks — sashlock variants listed for cottage pane doors