Cavity Sliding Door Hardware

Picture a new ensuite. The cavity slider has been framed in, the plasterer has been and gone, and the door arrives on site, only for someone to discover it's too thin for the privacy lock you picked. Or the lock sits in the hollow part of the door where there's nothing solid to cut into.

Cavity sliders save a lot of floor space, which is why they turn up in almost every renovation, from ensuites and laundries to walk-in robes and butler's pantries. But their hardware works differently from a hinged door, and a few decisions need to be made much earlier than most people expect.

This guide covers what cavity sliding door hardware is, which function you need for each room, and what to lock in before the wall is closed up.

Why cavity sliders need different hardware

A cavity (pocket) door slides into the wall, so anything sticking out of its face would catch on the frame as the door disappears. That rules out standard levers and knobs. Instead, cavity doors use hardware that sits flush with the door surface:

• Flush pulls: recessed cups set into each face of the door, which you grip with your fingertips to slide it.
• Edge pulls: a small recessed or flip-out pull on the leading edge of the door. When the door is fully open, the edge is often all you can reach, and the edge pull lets you draw the door back out of the wall.
• Sliding door locks: a mortice lock set into the door edge, usually with a hook-shaped bolt that engages a striker on the jamb. A normal latch won't work because the door moves sideways rather than swinging.

Most cavity sets combine these into one matched kit, so you get the pulls, edge pull and lock (where needed) in the same finish.

Flush pull shapes: rectangular, round or square

Flush pulls come in three main shapes, and the choice is mostly about style:

• Rectangular: the most common choice. The longer shape gives a comfortable grip and suits modern interiors and tall doors.
• Round: softer and more traditional, and a good match for round-rose levers elsewhere in the house.
• Square: a clean, architectural look that pairs well with square-rose levers.

A simple rule: match the flush pull shape to the rose shape on your hinged doors. If your passage levers are on square roses, square flush pulls will make the whole house look planned.

Shop: Rectangular flush pulls, round flush pulls, square flush pulls

Choosing the right function for each room

Cavity sets come in the same functions as hinged door handles. If you're new to the terms, our Door Handle Functions Guide explains them in detail.

The emergency release on a privacy set matters more than it seems. It lets you open the door from outside if someone needs help, which is especially important in homes with young children or elderly family members.

Shop: Rectangular privacy sets, round privacy sets, square privacy sets, rectangular entrance sets, sliding mortice locks

What to decide before the wall is sheeted

The cavity unit (the steel or timber frame the door slides into) goes in during the framing stage. Once the plasterboard is on, changing it means opening the wall again. So these decisions need to be made while the frame is still open.

1. Door thickness

   Every cavity lock and privacy set is designed for a specific range of door thicknesses, and ranges vary between brands and models. Check the specification of the exact set you want, then make sure your door and cavity unit both match it.

2. Backset

   On cavity locks, the backset is the distance from the door edge to the centre of the lock or turn. It also varies between products. If your door supplier is pre-machining the door, give them the lock's backset and fitting template before they cut. Our Backset Guide explains how backset works.

3. Solid material where the hardware goes

   Hollow-core doors only have solid timber in certain areas. Flush pulls and locks sit close to the leading edge, so confirm with your door supplier that there's solid material where the hardware will be cut in, or order a solid-core door.

4. Door weight and size

   Heavier solid doors need a cavity unit and track rated for the weight. This is a question for your cavity unit supplier, but it's much easier to sort out now than after the wall is finished.

5. Finish across the whole house

   Cavity sets are often ordered separately from the rest of the hardware, which is how finishes end up mismatched. Put your cavity doors on the same hardware schedule as your hinged doors. Our Finishes Guide can help you choose.

Installation tips

• Use the manufacturer's template. Flush pulls and locks need precise cut-outs, and a template avoids gaps around the recess.
• Check the striker alignment. The hook bolt must line up with the striker on the jamb, or the lock won't engage.
• Test the privacy lock with the door open first. Lock and release it a few times before closing the door, so nobody gets stuck during testing.
• Check the door can be retrieved. With the door fully open, make sure the edge pull is reachable. Many cavity units have an adjustable stop so the door stays slightly proud of the wall.
• Make sure nothing catches. Slide the door in and out several times to confirm no part of the hardware rubs on the cavity frame.