Shower over bath or walk-in shower: replacing a bath in NZ

Yes, you can usually replace a bath with a walk-in shower in New Zealand without a building consent, because the number of sanitary fixtures in the house stays the same: Schedule 1 clause 35 of the Building Act exempts that kind of plumbing alteration when an authorised plumber does it. Keep the bath and add a separate shower, and the count goes up, so you need consent.

Shower over bath or walk-in shower: which is better?

It depends on who uses the room. A shower over a bath is the classic New Zealand compromise: it fits a small room, gives you a bath for children and the odd soak, and costs least to redo. A walk-in shower is easier to get in and out of, roomier to stand in, simpler to keep clean, and looks more open. The trade-off is losing the bath.

Do I need consent to replace a bath with a shower?

Normally not, if you are swapping one for the other. Clause 35 of Schedule 1 exempts alterations to existing sanitary plumbing provided the total number of sanitary fixtures in the building does not go up and no specified system is affected. Take out a bath and put in a shower, and the count is unchanged. The exemption sits in the Part of Schedule 1 covering work by a person authorised under the Plumbers, Gasfitters, and Drainlayers Act, so the plumbing has to be done by an authorised plumber.

• Bath out, shower in: fixture count unchanged; normally exempt.
• Shower over bath replaced with a walk-in shower: fixture count unchanged; normally exempt.
• Bath kept, separate shower added: fixture count up by one; consent needed.
• Walls removed or moved, or floor framing cut to recess a level-entry shower: look harder. Structural changes are a different question from the plumbing; check with your council before anyone starts.

Our consent guide sets out both clauses in full, and the table there shows which common jobs fall where. Exemptions apply to the job as it actually is, so confirm yours with your council.

How much does it cost to replace a bath with a shower?

Start from the shower itself. Superior Renovations puts a new tiled shower at $1,550–8,250 across New Zealand and $2,000–9,500 in Auckland, and an acrylic shower unit at $900–2,000, without stating whether GST is included. Converting a bath adds removing it, moving the waste and mixer, rebuilding the floor where the bath sat, and making good the walls. In practice that usually means retiling the room, which is CheckMyBuilder's mid-range tier at $15,000–35,000 excluding GST.

For a figure on your own room, the bathroom renovation cost calculator works through size, scope and region, and the cost guide explains the tiers.

What goes wrong when a bath becomes a shower?

The floor. Under a bath, the floor mostly stays dry. Under a shower, it is wet every day, and Building Code clause E3 requires surfaces likely to be splashed to be impervious and built so water cannot get behind the linings or into concealed spaces. A tiled shower floor needs the right fall to the waste and a continuous membrane up the walls. On a timber floor, the substrate under that membrane has to be sound and stiff enough not to crack the tiles.

The other surprise is what's under the old bath. Leaks around a bath often go unnoticed for years, and stripping it out is when soft or rotten flooring turns up. Budget for it. Our waterproofing guide covers what the Code requires and what to photograph before tiling.

Will removing the bath hurt resale?

If it's the only bath in the house, it can narrow the pool of buyers, because families with young children often look for one. If there's a second bathroom with a bath, or the house suits buyers without young children, a well-built walk-in shower is usually seen as an upgrade. If you're unsure, a good-quality bath with a shower over it and a fixed glass screen keeps both options.