Auckland · Bathrooms
A bathroom is the most expensive room in the house per square metre, and the reason is arithmetic.
Seven trades visit a room the size of a parking space, most of them unable to start until the one before has finished, and one hold point in the middle where a council inspector has to see the waterproofing before anything covers it. Floor area barely enters into it.
$10,016 – $14,468
Modelled trade labour for a full bathroom rebuild in its existing footprint — 170 hours at published median pay rates, with a 1.8×–2.6× charge-out multiplier. Tiles, fittings, tapware, glass and the membrane system are not in this figure. Not a quote.
Modelled on this site from Tahatū Career Navigator pay bands — labour only, not a quote · July 2026
Photography commissioned — plate reserved · July 2026
The critical item
Everything in a bathroom is downstream of the waterproofing.
Tile choice is a preference. The membrane is not. It is the item that decides whether this room is a finishing job in eight years or a framing repair, and it is the only part of a bathroom that a council inspector generally wants to see before it disappears.
A wet area has to comply with Building Code clause E3, internal moisture. In practice that means a continuous membrane system, correctly detailed at every junction — floor to wall, waste penetration, shower threshold, hob — and installed on a substrate the membrane manufacturer actually accepts. The system is specified by the manufacturer, and departing from their detail is what voids it.
Restricted building work is defined narrowly, and internal tanking is not in the definition. But the consequence of getting it wrong lands squarely in restricted building work: water in the framing or in the external wall becomes a structural and weathertightness repair, and that must be carried out or supervised by a Licensed Building Practitioner. This is the same failure mechanism, at a smaller scale, that produced New Zealand’s weathertightness losses.
So the two questions worth asking a bathroom builder are: which membrane system, and who applies it. Not which tile.
Tertiary Education Commission — Tahatū Career Navigator · retrieved 2026-07-30
Tertiary Education Commission — Tahatū Career Navigator · retrieved 2026-07-30
The model
Seven trades, three to five square metres.
The scope modelled is a full strip-out and rebuild in the existing footprint: fixtures return to the same positions, the room is re-lined where needed, waterproofed, fully tiled, and a framed shower screen fitted. Pay rates are published; hours are judgement and printed so you can change them.
| Trade | Median hourly pay | Assumed hours (judgement) | Wage cost |
|---|---|---|---|
| Carpenter | $31.25 | 44 | $1,375 |
| Wall and floor tiler | $32.21 | 54 | $1,739 |
| Plumber | $35.10 | 26 | $913 |
| Electrician | $41.35 | 12 | $496 |
| Plasterer | $30.77 | 14 | $431 |
| Painter and decorator | $29.81 | 14 | $417 |
| Glazier | $32.21 | 6 | $193 |
Pay rates are the published median for each trade. The hours are this site’s judgement for the scope described above, not a measured figure — change the hours and the answer changes, which is exactly why no one can quote a renovation from a floor area.
Tertiary Education Commission — Tahatū Career Navigator · retrieved 2026-07-30
Photography commissioned — plate reserved · July 2026
From a wage to a price
The table above totals $5,565 of wages across 170 labour hours for a full bathroom rebuild in its existing footprint. That is not what the work costs you. A charge-out rate also has to cover ACC levies, annual and sick leave, vehicles, tools, insurance, supervision, quoting time that never converts, office overhead and margin.
Across New Zealand trades a charge-out rate of 1.8× to 2.6× the wage is the ordinary range. That multiplier is judgement — no official source publishes it — so it is stated here rather than buried, and you can substitute your own. Applying it gives a modelled labour component of $10,016 – $14,468.
Materials, fittings, appliances, consent and inspection fees, scaffolding, skips, temporary works and the builder’s margin all sit on top of that. The labour component is usually the largest single line in a renovation, which is why a decade of labour cost rises has moved renovation prices far more than any material has.
What to do
The order that keeps a bathroom out of trouble.
- 01
Settle the fixture positions
Same positions is materially cheaper and lower risk. Moving the toilet is the expensive decision, not moving the basin.
- 02
Specify the membrane system by name
Product, substrate and applicator. Then the compliance path is clear before anyone opens a wall.
- 03
Establish the consent position
Check the thresholds, then confirm with Auckland Council. Wet-area work usually carries an inspection hold point before tiling.
- 04
Plan for what is behind the lining
On a house of any age, budget for the possibility of wet framing. If it is there, the repair is restricted building work and needs a Licensed Building Practitioner.
- 05
Keep the records
Membrane certificate, inspection record, plumbing certification. They matter when you sell, and they matter more if anything ever leaks.
Questions people actually ask
Is bathroom waterproofing restricted building work?
Not automatically, and this is worth getting right rather than repeating the shorthand. Restricted building work is defined by the Building (Definition of Restricted Building Work) Order 2011 as work on a house’s primary structure or its external moisture-management system. Internal tanking of a wet area is neither of those, so on its own it is not restricted building work.
It is still consented work in most bathroom rebuilds, it must comply with Building Code clause E3 for internal moisture, and Auckland Council will inspect it before it is covered. And the moment the job touches framing, a bracing wall, a new window or the cladding — which a bathroom on an external wall very often does — that part is restricted building work and a Licensed Building Practitioner must do or supervise it. Only Auckland Council can confirm what applies to your address.
Why does a bathroom cost more per square metre than any other room?
Because almost every trade has to visit a room of three to five square metres. The model on this page puts 170 labour hours into that floor area — carpenter, tiler, plumber, electrician, plasterer, painter and glazier — and most of them cannot start until the one before has finished. Small floor area does not reduce the number of visits, the fixed setup cost of each trade, or the waterproofing hold points. Density of trades per square metre is what makes bathrooms expensive, and it is also why the $/m² framing is useless here.
Do I need consent for a bathroom renovation?
Replacing fittings in the same positions can fall inside the exemptions. Creating a new bathroom, moving sanitary plumbing or drainage, or altering structure generally needs a building consent. Because a bathroom is a wet area, the consent conditions usually attach an inspection of the waterproofing before tiling. The published thresholds are here — and they are the rules, not a ruling about your house.
What goes wrong most often?
Water leaving the room. The failures that turn a bathroom into a structural repair are almost all at junctions: the floor-to-wall corner, the waste penetration, the shower door threshold, and the tiled hob. None of them is visible after tiling, which is why the waterproofing inspection exists and why the membrane applicator, the substrate and the movement joints belong in your specification rather than in a conversation on site. A bathroom that leaks into a floor becomes a framing job, and framing repair is restricted building work.
Is tiling or a moulded liner cheaper?
A moulded shower or acrylic liner removes most of the tiler’s hours — published median $32.21 an hour, band $24.04 to $50.00, with 118 live Auckland listings — and it removes a set of junctions that can fail. It is cheaper and, in a rental or a tight footprint, often the better engineering answer. Fully tiled is a finish decision, not a performance one. That comparison is judgement; the pay figures behind it are published data.
How long is the room out of action?
Two to four weeks for a full rebuild in the existing footprint, longer if the waterproofing inspection has to be booked around the tiler’s availability, and longer again if anything behind the lining turns out to be wet. If it is the only bathroom in the house, treat that as part of the cost. Programme figures here are judgement, not published data.
Consent and zoning information on this page describes the published rules and the Auckland Unitary Plan zoning map. It is not a determination about your property, and only Auckland Council can confirm what applies to your address. Much of the work described here is restricted building work under the Building Act 2004, which must be carried out or supervised by a Licensed Building Practitioner. This site does not yet name the trade partner who would do the work, and until it does it claims no licence, guarantee or membership.
One route from here
Tell us whether the fixtures move.
That one answer, plus the age of the house and whether it is the only bathroom, is enough for an honest reply about scope, programme and whether your budget is in the right band.