Under-stair space is one of the most overlooked storage opportunities in a NZ home. With some basic carpentry skills, common materials, and a weekend or two, you can frame up a tidy cupboard that adds real everyday value. Here's how to approach the project safely and correctly.
First Things First: Do You Need a Building Consent?
Before picking up a hammer, check whether your project needs a building consent. In New Zealand, many minor internal alterations are exempt under Schedule 1 of the Building Act 2004, but the exemptions have conditions. Generally, a simple non-structural stud-framed cupboard inside an existing stairwell is likely exempt — but this depends on your specific situation, your council, and whether any structural elements are involved.
Always confirm with your local council before starting. You can find general guidance on consent exemptions at MBIE Building Performance. Getting this wrong can cause problems when you sell your home.
Plan the Space and Take Measurements
Start by measuring the full triangular void under the stairs:
- Height at the tallest point (usually where the stairs meet the upper floor or landing)
- Width of the available space
- Depth from the front face to the back wall
- Note the stringer (the angled side board of the stair) — your framing will follow this angle
Sketch a simple plan showing where the door opening will go, any shelving, and how the angled ceiling (the underside of the stair treads) will affect usable height. A door positioned at the tallest end makes access much easier.
Materials You'll Need
| Item | Notes |
|---|---|
| 90×45 mm framing timber | For stud walls and door frame |
| GIB plasterboard (10 mm standard) | For lining interior walls and ceiling |
| Timber or MDF shelving | Cut to suit your angles |
| Pre-hung or flat-pack door kit | Choose a size that suits your opening |
| Cornice and stopping compounds | For a tidy finish |
| Screws, nails, joist hangers | As required |
| Primer and paint | Resene or Dulux interior paint |
You'll find most of these at Mitre 10, Bunnings, or PlaceMakers.
Step-by-Step: Framing the Cupboard
1. Mark Out the Wall Line
Using a chalk line or straight edge, mark the front face of your new cupboard wall on the floor and ceiling (or underside of the stair). This is where your bottom and top plates will sit.
2. Fix the Bottom and Top Plates
Cut your 90×45 mm timber to length and fix the bottom plate to the floor (concrete anchors or nails into timber subfloor) and the top plate to the ceiling or stair structure above. Make sure they are plumb with each other.
3. Frame the Studs
Install vertical studs at 600 mm centres between the plates. Frame the door opening to suit your chosen door — typically 810 mm wide with a trimmer stud on each side and a lintel (nogging) across the top.
4. Follow the Stair Angle
The back wall and any internal framing will need to follow the rake of the stairs. Cut your top plates and studs at the matching angle — a sliding bevel gauge is handy here.
5. Line the Walls and Ceiling
Fix 10 mm GIB plasterboard to the framing. The angled ceiling under the stairs can be tricky — take your time measuring each sheet. Stop and paint to match your interior.
Adding Shelves and Finishing Touches
- Fixed shelves can be screwed to cleats (horizontal timber strips) fixed to the studs — strong and simple.
- Adjustable shelving using shelf-pin holes gives more flexibility as your storage needs change.
- Fit a door stop, hinges, and a handle or latch. A magnetic catch works well for a clean look.
- Add a light fitting inside the cupboard for practicality — see the electrical note below.
- Paint the interior a light colour to make the space feel larger and easier to see into.
Electrical Work: What You Can and Cannot Do
If you want a light inside the cupboard, electrical wiring is restricted work in New Zealand. Only a registered electrician can install new wiring, circuits, or fittings connected to your home's wiring. This is regulated by the Electrical Workers Registration Board (EWRB).
As a homeowner, you may be able to replace a like-for-like fitting in some circumstances, but any new circuit or cabling must be done by a licensed electrician. Always check before attempting any electrical work.
When to Call a Professional
Consider hiring a qualified carpenter if:
- You're unsure about the structural role of any existing framing or the stair stringer
- The project involves moving or modifying load-bearing walls
- You need a building consent and want the work done correctly for LIM/title purposes
- You're not confident with angled cuts, door hanging, or stopping and plastering
A skilled carpenter can typically complete a basic under-stair cupboard in one to two days. You can find experienced local carpenters on tradedirectory.co.nz.
For guidance on what work requires a Licensed Building Practitioner (LBP), visit LBP New Zealand.
