Hanging something heavy on the wall — whether it's a flat-screen TV, a large mirror, or a set of shelves — means you need to fix into a wall stud, not just the plasterboard. Plasterboard (also called GIB board in New Zealand) simply isn't strong enough on its own to hold significant weight, and a failed fixing can cause serious damage or injury. Here's how to find those studs with confidence.
Why Studs Matter in NZ Wall Construction
Most New Zealand homes are timber-framed, built to NZS 3604, which sets out the standard for light timber framing. Studs are the vertical timber members inside your walls, typically 90 mm × 45 mm in size. They are the structural backbone of your wall and the only reliable anchor point for heavy fixings.
The outer surface you see is usually GIB plasterboard, which is 10 mm or 13 mm thick. On its own, plasterboard can hold only very light items using cavity fixings — anything heavier needs to go into a stud.
How Far Apart Are Studs in NZ Homes?
In most NZ homes built to NZS 3604, studs are spaced at either 400 mm or 600 mm centres (measured from the centre of one stud to the centre of the next). Older homes may vary, and some walls — particularly around windows and doors — will have additional nogging or trimmer studs at irregular spacings. Once you find one stud, you can use the standard spacing as a guide to locate the next.
Method 1: Use a Stud Finder
A stud finder is the easiest and most reliable tool for the job. You can pick one up from Bunnings or Mitre 10 for a modest cost (as a guide, basic models start from around $30–$50, though prices vary).
How to use a stud finder:
- Place the tool flat against the wall and press the activation button.
- Slowly slide it horizontally across the wall.
- When it beeps or the indicator lights up, you've likely found the edge of a stud.
- Mark both edges of the stud, then find the centre — that's where you'll drill.
- Confirm by repeating the scan from the other direction.
Tip: Stud finders can give false readings near power points, pipes, or areas with multiple layers of material. Always double-check with another method if you're unsure.
Method 2: The Knock Test
This old-school technique costs nothing. Knock firmly along the wall with your knuckle, moving horizontally. The sound will be hollow between studs and produce a slightly duller, denser thud directly over a stud. It takes a bit of practice, but it works well once you get your ear in.
Method 3: The Magnet Trick
A strong rare-earth magnet (or even a magnetic stud finder) can detect the nails or screws used to fix the plasterboard to the studs. Run the magnet slowly across the wall — when it sticks or pulls, you've found a fixing point, which means a stud is directly behind it.
Method 4: Look for Visual Clues
Sometimes the wall itself gives you hints:
- Skirting board nails are usually driven into studs — look for small nail holes or filled spots along the top of the skirting.
- Power points and light switches are almost always fixed to a stud on at least one side.
- Measure 400 mm or 600 mm from a known stud location to estimate the next one.
Confirming Your Find Before You Drill
Before committing to a hole, drive a thin nail or bradawl into the wall at your marked spot at a slight angle. If it meets solid resistance after passing through the plasterboard, you've hit a stud. If it goes straight through with no resistance, you've missed — try again 25–50 mm to either side.
Choosing the Right Fixings
Once you've located your stud, use appropriate structural screws — typically 65 mm to 75 mm timber screws — to fix your bracket or fitting directly into the stud. For very heavy loads (like a large wall-mounted TV or a heavy bookshelf), use multiple fixings across more than one stud where possible.
| Item to hang | Recommended fixing method |
|---|---|
| Light picture (under ~5 kg) | Cavity anchor into plasterboard |
| Medium shelf or artwork (5–15 kg) | Single stud with structural screws |
| TV bracket or heavy shelf (15–50 kg) | Two or more studs, heavy-duty screws |
| Over 50 kg (e.g. large cabinet) | Consult a carpenter |
What to Watch Out For: Pipes and Wires
Before drilling into any wall, be aware that electrical cables, water pipes, and gas lines can run through or alongside studs. WorkSafe NZ recommends using a multi-scanner that detects both studs and live wires before drilling. If in doubt — especially in wet areas like kitchens and bathrooms — don't guess.
When to Call a Professional
If you're mounting something very heavy, fixing into a wall you're unsure about, or working near electrical wiring or plumbing, it's well worth getting a qualified tradesperson involved. A Licensed Building Practitioner (LBP) or experienced carpenter can assess your wall, confirm stud locations, and ensure your fixings are safe and compliant. You can find trusted local carpenters on tradedirectory.co.nz.
For anything involving electrical work — such as installing a wall-mounted TV with in-wall cable management — that work must be carried out by a registered electrician under the Electrical Workers Registration Board (EWRB) rules. DIY electrical work is restricted and illegal in New Zealand.