Apply the answer
Check the scope before judging the price.
Put GST, product and major inclusions on the same basis first. RoofHub will tell you when the comparison is incomplete rather than forcing a verdict.
How do you make two roofing quotes comparable?
- Confirm whether each total includes GST.
- Confirm the proposed roofing system, profile, coating or finish and any stated thickness or grade.
- Match removal and disposal of the existing roof.
- Match scaffold, edge protection and difficult-access allowances.
- Match underlay, flashings, penetrations and rainwater work.
- Identify timber, substrate or structural repairs that are excluded or provisional.
- Record warranties, programme, payment terms and the process for variations.
New Zealand GST is 15%. RoofHub only normalises a quote when you tell us whether its amount includes or excludes GST. An unknown GST basis is a reason to stop the price comparison, not a reason to guess. Sources: Inland Revenue; Commerce Commission.
What is the difference between a quote and an estimate?
| Document | What it means | What to clarify |
|---|---|---|
| Quote | An offer to do specified work for a stated price once accepted. | Exact scope, exclusions and how variations will be agreed. Sources: Consumer Protection; Commerce Commission. |
| Estimate | A best estimate or range based on the information and assumptions available. | Limits, assumptions and what could cause the final price to change. Sources: Consumer Protection; Commerce Commission. |
Commerce Commission guidance says extra work outside an accepted quote needs customer agreement before the price changes. For estimates, significant possible variation and its conditions should be made clear. Sources: Commerce Commission.
Why can roofing quotes be far apart?
RANZ notes that differences may come from what is included, which roofing material or system is proposed, and how the work will be carried out. Consumer Protection similarly recommends looking beyond price at experience, reliability, quality standards, references and past projects. Sources: Roofing Association of New Zealand; Consumer Protection.
If the totals are far apart, ask each contractor to explain the scope in writing. A clearer quote is often more useful than a lower headline number with unresolved exclusions. Sources: Consumer Protection.
When does the written building contract threshold matter?
For residential building work costing $30,000 or more including GST, Building Performance says a written contract is required. The contractor must also provide the consumer protection standard checklist and disclosure statement at that threshold, or if the homeowner asks for them. Sources: Building Performance.
A roofing quote and a building contract are related but not interchangeable documents. The accepted scope should flow into the contract, including payment, variations, responsibilities and any exclusions that matter to the project. Sources: Building Performance.
What should you do before accepting a roofing quote?
- Resolve any unknown GST basis.
- Ask for the exact roof product or system where the description is vague.
- Make major inclusions and exclusions explicit.
- Ask what could become a variation and who approves it.
- Check relevant experience, references and business information.
- Read warranty conditions rather than comparing warranty years alone.
- For residential building work at or above the statutory threshold, make sure the written contract and required disclosure information are in place.
Related questions
Does the lowest roofing quote mean the best value?
Not necessarily. Compare the same roof system and scope, then consider contractor experience, reliability, quality standards, references, warranties and the proposed way of carrying out the work. Sources: Consumer Protection; Roofing Association of New Zealand.
Should a roofing quote include GST?
Commerce Commission guidance says quotes or estimates should be inclusive of GST. If a document is unclear, ask the contractor before comparing totals. Sources: Commerce Commission.
Sources and review notes
Prepared by RoofHub editorial team. Reviewed . A source check confirms what a page states, not an independent inspection or invoice audit. Published project accounts are attributed to their publishers.
- primaryConsumer Protection: Quotes and estimates - NZ government consumer guidance reviewed 21 October 2026. Distinguishes quotes from estimates, says accepted fixed quotes can only change where a variation is agreed, and states there is no legal requirement to pay a deposit; if one is requested, its consumer guidance says not to pay more than 10% of total cost. Page checked 2026-10-21. Publication date not stated. · government
- primaryRoofing Association of New Zealand: Comparing Quotes - RANZ guidance reviewed 20 October 2026. Explains that roofing quotes may differ because of scope, materials, systems and how work will be carried out, so a price difference alone is not a quality conclusion. Page checked 2026-10-20. Publication date not stated. · industry-technical
- primaryCommerce Commission: Quotes, estimates and invoicing - NZ Commerce Commission guidance reviewed 20 October 2026. Defines quotes and estimates, requires agreement for extra work outside an accepted quote, and states quotes or estimates should be inclusive of GST. Page checked 2026-10-20. Publication date not stated. · government
- primaryInland Revenue: What GST is (2026-04-01) - Inland Revenue page last updated 1 April 2026. Confirms the standard NZ GST rate is 15%. Used only to normalise explicitly GST-exclusive figures, not to guess whether an unstated source price includes GST. Page checked 2026-10-20. Publication date shown above. · government
- primaryBuilding Performance: Contracts for your building project (2026-01-15) - Building Performance guidance last updated 15 January 2026. Residential building work costing $30,000 or more including GST requires a written contract; disclosure and checklist requirements also apply at that threshold or when requested. Page checked 2026-10-21. Publication date shown above. · government
Original calculations are labelled as examples. Historical prices stay dated, missing fields stay unknown, and conflicting specifications are flagged. Sources are not endorsements or paid rankings. Read our methodology or report a correction.
Keep exploring
Next step
Estimate it, refine it, or ask RoofHub.
Start with approximate information, use actual measurements when you have them, or ask RoofHub to explain the decision. A roofing contractor still needs to confirm the site, specification and final quotation.