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NZ Building Code · Linings & GIBGIB Aqualine wet area board
GIB Aqualine is the green, moisture-resistant plasterboard for showers, bathrooms and laundries — the stable backing your E3 membrane sits on, not the waterproofing itself.
GIB Aqualine® is the green-paper, moisture-resistant plasterboard for showers, bathrooms and laundries (BRANZ Appraisal No. 427). The key thing to get right: Aqualine resists humidity and incidental splash, but it is not a waterproofing layer on its own. In a shower you still need a proper E3 membrane over it — the board just gives that membrane a stable, moisture-tolerant backing.
Which thickness to use
Both sheets come with a rebated edge for taping. Pick the thickness by the job:
- 10mm Aqualine – residential bathrooms, laundries and en-suites.
- 13mm Aqualine – commercial and light commercial work, taller walls (over 2.7m), and shower stalls with tile.
Internal corners
BRANZ Appraisal 427 calls for a 32×32×0.55mm galvanised metal angle at 600mm centres in shower internal corners, fixed under the membrane. A couple of buying notes:
- Available from PlaceMakers or ITM by the linear metre, around $8/lm.
- It is not a stocked GIB SKU — buy it separately.
Fixings and floor gap
Fix off with 32×6g GIB Grabber HighThread screws, spaced to suit the wall:
- Tiled walls – screws at 150mm centres.
- Non-tiled walls – screws at 300mm centres plus adhesive daubs.
- Leave a 5–10mm gap at the floor for the membrane upturn.
Where it can’t go
A few hard limits to keep in mind:
- Bracing is not allowed in shower cubicles (a B2 durability concern).
- Not for steam rooms or indoor pools.
- Don’t use standard plasterboard in wet areas — use Aqualine or Villaboard.
Plain-English guide, not advice. This page helps you understand and navigate the rules — it is general information, not design, engineering or consent advice, and it does not reproduce the copyrighted tables of NZS 3604 or any Standard. Always check the current Standard or Acceptable Solution and your BCA, and use a suitably qualified LBP, engineer or QS where it matters.
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Common questions
Is GIB Aqualine waterproof on its own?
No. Aqualine resists humidity and incidental splash, but it is not a waterproofing layer by itself. In a shower you still need a proper E3 membrane over it — the board just gives that membrane a stable, moisture-tolerant backing.
When do I use 10mm vs 13mm Aqualine?
Use 10mm Aqualine for residential bathrooms, laundries and en-suites. Use 13mm Aqualine for commercial and light commercial work, taller walls over 2.7m, and shower stalls with tile.
How far apart should the GIB Grabber screws go?
On tiled walls, fix 32×6g GIB Grabber HighThread screws at 150mm centres. On non-tiled walls, fix at 300mm centres plus adhesive daubs, and leave a 5–10mm gap at the floor for the membrane upturn.
What goes in the shower internal corners?
BRANZ Appraisal 427 calls for a 32×32×0.55mm galvanised metal angle at 600mm centres in shower internal corners, fixed under the membrane. It’s sold by the linear metre from PlaceMakers or ITM (around $8/lm) and is not a stocked GIB SKU, so buy it separately.
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