What the law says, in plain words
Building work must be done under a building consent unless the law exempts it. Schedule 1 of the Building Act lets you repair and maintain parts of a building without a consent if a comparable product is used, and replace parts without a consent if a comparable product is used in the same position.
That exemption does not cover complete or substantial replacement of a part that contributes to the building's structure or fire safety. Nor does it cover repair or replacement (other than maintenance) of a part that failed the Building Code's durability rules, for example by letting in water.
Exempt work still has to meet the Building Code. It must not leave the building less compliant than it was before, and it must not breach any other law, such as the district plan.
What councils say about like-for-like re-roofing
New Plymouth District Council gives replacing roofing with the same type of roofing, where the old roof is more than 15 years old, as a typical example of work that doesn't need a building consent.
Wairoa District Council says like-for-like re-roofing, such as new corrugated iron replacing old corrugated iron with no change to the purlins, doesn't need consent unless the cladding failed within 15 years. Changing the purlins or the roofing system, for example corrugated iron to pressed metal tiles, does need consent.
MBIE's own exemptions guidance goes a little further. Its exempt examples include replacing 20-year-old profiled metal roofing with a comparable product, and replacing an old clay tile roof with profiled metal, such as longrun or pressed metal tiles, in the same position, though it notes things like higher uplift forces still have to be considered. Its example of work that does need consent is replacing old corrugated iron with concrete tiles, because the heavier tiles load up the existing structure.
So councils don't all read the rules the same way, and yours may see a borderline job differently. Ask.
Usually exempt, or usually needs consent?
| Usually exempt | Usually needs consent | |
|---|---|---|
| The roofing | The same type of roofing, or (in MBIE's example) old clay tiles replaced with profiled metal in the same position | A heavier roof, such as corrugated iron to concrete tiles. Some councils, such as Wairoa, also count lighter changes like corrugated iron to pressed metal tiles |
| The framing | Purlins left as they are | Purlins changed |
| Why it's being replaced | It's simply old (one council's example is a roof over 15 years old) | It failed early, for example by letting in water |
| Smaller jobs | Repairs and maintenance with a comparable product | Complete or substantial replacement of a structural part |
| Solar panels | Arrays totalling no more than 40 square metres on a structurally fixed frame, within the wind limits | Bigger arrays or windier sites, unless a chartered professional engineer designs or reviews the work |
Going lighter, or going heavier
Which way the weight goes matters. MBIE's guidance treats replacing an old clay tile roof with profiled metal in the same position as exempt, while going from corrugated iron to heavier concrete tiles needs consent because of the extra load on the framing.
Not every council reads it so generously. Wairoa District Council says changing the roofing system needs consent, and so does changing the purlins, which a roofer may need to do to suit a new roof. Decramastic to longrun raises the same question, covered on our decramastic to COLORSTEEL page.
There's a good reason people go lighter. The Natural Hazards Commission says a single roof tile can weigh up to 4.5 kg, and recommends replacing concrete or slate tiles with lighter options such as corrugated iron or metal tiles, or making sure tiles are well secured to the framing.
MBIE also says it's the homeowner's job to decide whether work is exempt and to make sure it meets the Building Code. If you're unsure, it suggests asking the council for a discretionary exemption or applying for a consent, and it warns that non-compliant work can affect your insurance and a future sale.
Character areas and heritage homes
A building consent is about the Building Code. Your district plan is a separate set of rules, and in character or heritage areas it can control what a roof looks like, which can mean a resource consent as well.
In Auckland's Special Character Areas Overlay (Residential), restoration and repair of a building is a permitted activity, but external alterations or additions need resource consent as a restricted discretionary activity. In some areas, such as Isthmus A, demolishing 30% or more (by area) of a building's wall elevations and roof areas also needs resource consent. Auckland's Plan Change 120 may change these rules.
Heritage New Zealand says you need an archaeological authority before works that may modify or destroy a pre-1900 structure. If your house is that old, ask the council and Heritage New Zealand before you book a date. Our villa re-roof guide covers older homes in more depth.
How to find out for your house
Gather the basics
Note what the roof is now, roughly how old it is, what you want on it next, and whether it has leaked. Photos from the ground help.
Ask the roofer
A roofer who re-roofs in your area every week will usually know how your council treats like-for-like work. Ask them to put their view in writing on the quote.
Ask the council if there's any doubt
A council can also decide a consent isn't needed for particular work, if it considers the finished work is likely to comply with the Building Code. Ask before work starts, not after.
If consent is needed, plan the timing
Councils must grant or refuse a standard application within 20 working days, and the clock stops while they wait for information they've asked for. A consent lapses if work hasn't started within 12 months of being issued, unless the council allows longer.
Name the LBP
Consented re-roofing is restricted building work. Before it starts, tell the council the name of every LBP who will do or supervise it, if they weren't named in the application. Our guide to checking an LBP shows how to look them up.
Close it out
Once the work is finished, apply for the code compliance certificate as soon as practicable and include the Records of Work. The council must decide within 20 working days of your application.
What if work is done without a consent it needed?
Building work done without a required consent can bring a fine of up to $200,000, plus up to $10,000 for every day the offence continues. Councils can also issue a $1,000 infringement fee.
If you've bought a house where consentable roofing work was done without one, the owner can apply to the council for a certificate of acceptance for the work already done.
If the old roof might be asbestos
The consent question doesn't change the safety rules. If your home was built before 1 January 2000, the old roofing, ridge capping or spouting (gutters) may contain asbestos. Get it tested before anyone cuts, drills or lifts it. Removing more than 10 square metres of non-friable asbestos needs a licensed removalist.
What's on you, and what's on the roofer
You can
- Ask the council when you're unsure, before work starts
- Tell the council the LBP names for consented work
- Apply for the code compliance certificate when it's done
- Keep the consent, Records of Work and certificate with your house papers
Leave to a roofer
- Telling you honestly whether the job is like-for-like
- Preparing or helping with the consent application, if your contract says so
- Building to the consent, and telling you and the council if work doesn't comply
- Giving you and the council a Record of Work
Our rule of thumb
If the same kind of roof is going back on the same framing because the old one has simply worn out, we'd expect no consent, and we'd still get the roofer to say so in writing. If anything is changing, whether it's the material, the purlins or the reason it's being replaced, we'd ring the council first. A phone call now costs far less than a certificate of acceptance later.
Want a roofer to take a look?
Tell us the job and your postcode. We match it with a Find My Roofer certified roofer who specialises in that kind of work, and they call you to quote. Your number goes to them alone.