Bathroom renovation questions, answered with sources
Twenty-one answers on cost, consent, licensing and how we work. Every figure and every rule carries the source it came from.
Cost
How much does a bathroom renovation cost in NZ?
About $22,000 excl. GST for a typical job, with most mid-range renovations $15,000–35,000 and cosmetic refreshes from about $8,000 (CheckMyBuilder, July 2026). Premium work with structural changes runs $35,000–70,000. The full breakdown.
Is a small bathroom much cheaper?
Less than you would think. Superior Renovations puts fixed trade costs in Auckland at $10,000–15,000 regardless of room size, and the tiles-and-membrane difference between a 5 m² and a 10 m² room at perhaps $1,000–2,000. Its NZ-average small-bathroom bands are $4,000–8,000 for a minor upgrade and $15,000–25,000 for a full renovation.
Why are your ranges so wide?
Because the published bands are wide and narrowing them without evidence would be inventing precision. CheckMyBuilder's mid-range tier alone runs $15,000–35,000. A visit to your actual room narrows it; a website cannot.
Do your figures include GST?
CheckMyBuilder states its figures exclude GST. Superior Renovations does not state a GST status, so wherever we use a Superior figure the page says so and the number is used exactly as published. Our own price, the $395 visit, is incl. GST.
How much contingency should I hold?
15–20% (Superior Renovations), which on a $30,000 budget is $4,500–6,000. We show it as its own line on every estimate rather than hiding it inside a total.
What does moving the toilet or shower add?
$2,000–6,000 excl. GST on top of the job, for re-routing waste and water plus the waterproofing that follows (CheckMyBuilder).
Consent and rules
Do I need a building consent to replace a tiled shower?
Usually not. MBIE Determination 2024/054 (2 October 2024) decided that a wet-area membrane under tiled shower walls is part of the internal linings covered by Schedule 1 clause 12 of the Building Act, so replacing a tiled shower in an existing dwelling did not need consent. The clauses in full. Check your own job with your council before anyone starts.
What takes a bathroom outside the exemption?
Adding a sanitary fixture the house did not have, or modifying or affecting a specified system. Schedule 1 clause 35 only exempts alterations where the total number of sanitary fixtures in the building does not increase. Structural work is restricted building work and needs a Licensed Building Practitioner.
Does exempt mean it does not have to meet the Building Code?
No. Determination 2024/054 records that building work must comply with the Building Code to the extent required whether or not consent is obtained. The same determination found showers that needed no consent and still failed clauses E3.3.4, E3.3.5 and E3.3.6.
What records should I keep if there was no consent?
Dated membrane photographs, the membrane product data and installation instructions, the plumber's registration details, the electrician's certificate of compliance and the fan specification. There is no council paper trail on exempt work, so yours is the only one. The checklist.
What if my house was built before 2000?
WorkSafe says it may contain asbestos, including asbestos cement in wet-area linings, in the backing behind wall tiles, in vinyl floor tiles and the adhesive under them, and in textured ceilings. You cannot tell by looking: the only way to confirm it is to test a sample, done by a reputable contractor, before anything is removed. What to test.
Does a rental bathroom have extra rules?
Yes, the healthy homes ventilation standard. A bathroom fan installed after 1 July 2019 must be at least 120mm in diameter including ducting, or move at least 25 litres per second, and must vent outside. Tenancy Services advises landlords to get the diameter, ducting and flow rate in writing.
Who does the work
Who actually does the plumbing and waterproofing?
A partner bathroom crew does the strip-out, carpentry, waterproofing and tiling. A licensed plumber does the sanitary plumbing and a registered electrician does the prescribed electrical work. We are the contracting party and none of those licences are ours. How it works.
Can I do any of it myself?
Not the plumbing. The PGDB states that homeowners cannot fix or unfix sanitary plumbing, and the Schedule 1 plumbing exemptions only apply to work by an authorised person, so DIY would also take the job outside the exemption. Prescribed electrical work needs a registered electrical worker.
Is the waterproofer licensed?
No. Applying a wet-area membrane is not a licensed trade in New Zealand, which is why we ask instead which membrane system is used, whether the applicator is trained in it, and require every coat to be photographed.
What is plumber self-certification?
From 7 September 2026 a certifying plumber or drainlayer can apply to the PGDB for a self-certification endorsement. It only applies where the work needs a building consent: you can use an endorsed plumber who self-certifies, or have a building consent authority inspect it. Only endorsed plumbers can self-certify, and you can check the endorsement on the public register.
Do I need a Master Plumber?
No. Master Plumbers is a trade association, not a licence. The legal requirement is PGDB authorisation, which you check on the public register.
Working with us
Why pay for a visit when everyone else comes free?
Because a free visit is a sales call and the plan belongs to whoever paid for it. Ours is $395 incl. GST, takes 60 to 75 minutes, and produces a scaled plan, a line-item budget and a consent check that are yours whether or not we build the job. Build with us and it comes off the job in full.
What happens in the visit?
We measure the room and every fixture, photograph each wall and the floor, take non-invasive moisture readings around the shower and bath, look at the subfloor from below where there is safe access, and check the fixtures, waste positions and extractor fan.
When do I pay for the renovation?
Nothing until there is a signed fixed-price contract, then in stages against work that has actually happened: 20% on signing less your visit credit, 35% at strip-out and rough-in, 35% at membrane and tiling, 10% on completion released with the records pack. Pricing.
Can I get a refund on the visit?
In full, until 24 hours before the confirmed time, or if we cannot offer a visit within 10 working days of payment, or if the plan is not with you within 5 working days of the visit. After delivery it is not refundable, because you have the plan, and it is still credited to a contract signed within 6 months.
Why can't I book right now?
Because no bathroom crew, plumber or electrician is contracted in your area yet, and we will not take money for a visit we cannot deliver. Joining the waitlist costs nothing and reserves nothing.
Do you have reviews or completed projects to show me?
No, and we are not going to invent any. There are no reviews, no ratings, no job counts and no project gallery on this site, because there are no jobs yet. What we can show you is where every number here came from. Editorial policy.
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