Installing a sliding door cavity frame is a satisfying project that many capable DIYers can tackle — but whether you should do it yourself depends on where the door is going, what work is involved, and whether a building consent is required. Here's what you need to know before you pick up a hammer.
What Is a Cavity Slider Frame?
A cavity slider (also called a pocket door) slides into a concealed frame built inside the wall cavity, rather than swinging open. The frame is a pre-built steel or timber skeleton that sits between your wall studs and carries the door track, guides, and hardware. Popular NZ brands include Hettich, Hafele, and Cavity Sliders NZ — all widely stocked at Bunnings and Mitre 10.
Do You Need a Building Consent?
This is the most important question to answer before you start. Under the NZ Building Act, some work is exempt from building consent under Schedule 1, but the exemptions have conditions.
- Like-for-like replacement of an existing cavity slider (same opening, no structural changes) is generally exempt under Schedule 1.
- Creating a new opening in a wall — especially a load-bearing wall — almost certainly requires a building consent and must comply with NZS 3604 (Timber-framed buildings) for lintel sizing and structural support.
- Non-load-bearing internal walls may qualify for a Schedule 1 exemption, but you must still meet the NZ Building Code.
Always confirm with your local council before starting. The rules can vary and the consequences of getting it wrong — structurally or legally — can be significant. You can find general guidance at MBIE Building Performance.
Is It Restricted Work?
Carpentry itself is not restricted work in the same way that electrical or plumbing is — a homeowner can legally carry out their own carpentry. However:
- If the work involves electrical wiring (e.g. relocating a light switch or power point in the wall), that is restricted electrical work and must be done by a registered electrician. See EWRB for what's covered.
- If the work involves plumbing or drainage, that is restricted work under the Plumbers Gasfitters & Drainlayers Board.
- If a building consent is required, the work may need to be carried out or supervised by a Licensed Building Practitioner (LBP), particularly for Restricted Building Work (RBW) such as structural alterations.
Tools and Skills You'll Need
Before committing to a DIY install, honestly assess whether you have:
- Basic carpentry skills — measuring, squaring, cutting timber accurately
- Tools — spirit level, circular saw or mitre saw, drill/driver, stud finder, tape measure
- Ability to work safely — especially if cutting into existing walls (watch for hidden wiring and pipes)
- Time — a first-timer should allow a full weekend for a single door installation
Step-by-Step Overview
1. Plan and measure
Measure your door opening carefully. Cavity slider kits are sized by door dimensions — confirm the rough opening size required in the manufacturer's instructions. Allow for wall lining thickness on both sides.
2. Check the wall
Use a stud finder to locate studs, noggins, and any services (pipes, cables) hidden in the wall. If in doubt, cut a small inspection hole first.
3. Frame the opening
If creating a new opening, install a correctly sized lintel over the opening to carry any load above. Lintel sizing must comply with NZS 3604 — if you're unsure, get advice from a carpenter or structural engineer.
4. Install the cavity frame kit
Follow the manufacturer's instructions precisely. Most kits are assembled flat then tilted into position. Check for plumb, level, and square at every stage — a frame that's out even slightly will cause the door to bind or drift.
5. Fix and brace
Nail or screw the frame to the surrounding structure as specified. Add noggings where wall linings will be fixed.
6. Wall lining and finishing
Once the frame is in, GIB plasterboard or other wall lining goes on. Stopping, painting, and architrave finishing complete the job.
7. Hang the door
Hang the door on the track, adjust the rollers, and fit the floor guide. Test the action — it should glide smoothly with no binding.
Common Mistakes to Avoid
| Mistake | Why It Matters |
|---|---|
| Not checking for services in the wall | Risk of cutting through wiring or pipes |
| Frame not plumb or square | Door will bind, drift, or not latch |
| Undersized lintel | Structural risk — can cause wall to sag |
| Skipping council consent check | Potential fines, insurance issues, problems at sale |
| Wrong kit size | Door won't fit or hardware won't align |
When to Call a Professional
Consider hiring a qualified carpenter if:
- The wall is load-bearing and you're not confident sizing or installing a lintel
- A building consent is required and the work qualifies as Restricted Building Work
- You find unexpected services (wiring, pipes) inside the wall
- You're not confident your framing is plumb and square
- The project involves exterior walls or weathertightness considerations under NZ Building Code clause E2
A skilled carpenter can often complete a cavity slider installation in a day, giving you peace of mind that it's done right. You can find qualified local carpenters on tradedirectory.co.nz.
