Can You Fit a Smart Lock on a Narrow Aluminium Stile Door

Most smart lock marketing photos show a full timber front door, and for good reason — that's the majority of the market. But a genuinely common question we get is about the other kind of door: narrow aluminium-framed doors and sliding glass doors, common on units, townhouses, patios and newer builds. The honest answer is yes, but not with just any lock in the range — narrow stiles need a specific approach, and getting the measurement system right matters even more here than on a standard timber door.

What Actually Makes a Stile "Narrow"

The stile is the vertical frame member running down the edge of a door — on a solid timber door it's typically wide enough to comfortably fit a 60mm or 70mm backset lock with room either side. On an aluminium-framed glass door, the stile is often a fraction of that width, sometimes as narrow as 25–45mm of usable aluminium framing around the glass panel. That narrower dimension is why a standard lock physically can't go in: the internal mechanism and the backset it requires simply don't fit inside the available metal, regardless of how the handle looks from outside.

These doors are everywhere in Australian residential and commercial construction, even if the term "narrow stile" itself isn't widely known outside the trade. Sliding patio doors, shopfront-style entries on newer townhouses, courtyard doors framed in powder-coated aluminium, and internal glass office partitions all share this same narrow-frame construction. The appeal for builders is largely aesthetic and structural — a slim aluminium frame lets in more glass and light than a chunky timber stile would, and aluminium doesn't warp or swell with humidity the way timber can over time. The trade-off is that anything designed to retrofit onto a standard timber door's hardware footprint simply has nowhere to go on a frame this size.

Backset vs Centres: The Measurement Actually Changes

On a standard timber door, backset is the number that matters — the distance from the door's edge to the centre of the handle hole, as we cover in our backset guide. Narrow aluminium doors use a different system entirely: centres, the distance between the handle spindle and the thumbturn or lock cylinder, measured vertically rather than from the door's edge. This isn't a variation on backset — it's a different measurement describing a different kind of door construction, and the two numbers are not interchangeable or convertible into each other.

The Purpose-Built Option: SL-C1

Our Built-in Camera lock is specifically engineered for narrow aluminium stiles, with a 22mm backset and six centre options covering 147mm through to 240mm. If your door is genuinely narrow — the kind where a standard timber-door lock was never going to be a contender — this is the model built for that exact constraint, not a workaround. It also happens to add a video peephole with Wi-Fi built in, which suits the unit or townhouse doors this backset most commonly appears on.

The six centre options exist because narrow-stile hardware, unlike the fairly standardised 60/70mm world of timber doors, genuinely varies more between manufacturers and eras of construction. A door fitted with aluminium framing from one supplier in the early 2000s may use a different centre spacing than a comparable door installed by a different builder five years later, even though both would be described the same way — "narrow aluminium stile" — by anyone not measuring closely. Offering six options rather than one is a direct response to that real-world variation, not an attempt to make the ordering process more complicated than it needs to be.

✓ Built for 22mm narrow stiles

Smart Door Lock with Built-in Camera

22mm backset, six centre options from 147mm to 240mm — purpose-built for aluminium and glass-framed doors.

$539.99 AUD

View Product →

Want Fingerprint Instead of a Camera? SL-H1 Also Has a Narrow Option

Not every narrow-stile door needs a camera. Our Fingerprint & Code lever lock, better known for its standard 60mm/70mm timber-door backset, is also available in narrow-stile centre options of 147mm, 160mm and 180mm — the same centre measurements as SL-C1's range. If fingerprint and keypad entry matter more to you than a built-in camera, this gives you a genuine second option for the same style of door, rather than assuming SL-C1 is the only narrow-stile choice in the range.

This matters most for anyone comparing the two models purely on entry method rather than features. SL-C1's headline is the camera and video peephole; SL-H1's is fingerprint speed and the built-in doorbell button. Both being available in matching narrow-stile centres means the fit question and the feature question can genuinely be decided separately — you're not forced to pick a camera lock just because it happens to be the one that fits your aluminium frame, and vice versa. Confirm your exact centre measurement first, then choose between the two on what each one actually does at the door.

There's a third route if the door is framed glass or a sliding door: the short-handle push/pull lock (SL-P2, in black or silver) was designed for exactly those doors, where a full-length handle would foul the frame. Its narrow options are the 3585 and 2885 mortise codes, and two hook-bolt versions exist for doors that run on a track, because a straight bolt has nothing to grip on a sliding door.

✓ Narrow-stile centres available

Smart Door Lock — Fingerprint & Code

147mm, 160mm or 180mm centre options for narrow-stile doors, alongside the standard 60/70mm timber backset.

$349.99 AUD

View Product →

Explore the Full Range

If your door is a standard timber front door rather than narrow aluminium, our backset guide is the right one to read instead. And if you're comparing entry methods before you even get to fit, fingerprint vs keypad code and TTLock vs Tuya cover those decisions.

Frequently Asked Questions

Can any of your locks fit a narrow aluminium door?
Yes — the Built-in Camera lock (SL-C1) is purpose-built for narrow stiles with a 22mm backset, our Fingerprint & Code lever lock (SL-H1) also offers narrow-stile centre options, and the short-handle push/pull lock (SL-P2) covers narrow stiles and framed glass.

What's the difference between backset and centres?
Backset is the distance from a door's edge to the handle hole, used on standard timber doors. Centres is the distance between the handle spindle and lock cylinder, used on narrow aluminium and glass-framed doors. They're different measurements, not interchangeable.

How do I measure centres on my door?
Measure the vertical distance between the centre of the handle spindle and the centre of the lock cylinder or thumbturn. Our sizing guide shows this with diagrams.

Will a standard 60mm backset lock fit a narrow door if I'm careful?
No. The backset required is usually far larger than the available aluminium stile width — this isn't a tight-fit situation, it's a genuine size mismatch that no amount of careful installation solves.

Does SL-C1 work on sliding glass doors too?
SL-C1 is built for hinged narrow-stile doors. Sliding doors need a hook-bolt mechanism instead of a straight bolt — the short-handle push/pull lock (SL-P2) has two hook-bolt versions made for exactly that.

Which centre measurement is most common on Australian narrow-stile doors?
There's genuine variation — 147mm and 160mm are common, but always measure your specific door rather than assuming. Both SL-C1 and SL-H1 offer multiple centre options precisely because there's no single standard.

Key Takeaways

• A "narrow stile" is the slim frame edge on aluminium or glass-framed doors — far too narrow for standard timber-door locks.
• Narrow doors use centres, not backset — a different measurement entirely, not a smaller version of the same number.
• SL-C1 is purpose-built for narrow stiles (22mm backset); SL-H1 also offers narrow-stile centre options for fingerprint entry; SL-P2 covers narrow stiles and sliding doors.
• Never assume a standard-backset lock will "just fit" a narrow frame — measure and confirm centres first.
• Standard timber door instead? Read our backset guide.
• Browse the full range in Smart Door Locks, or check the sizing guide before ordering.