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Methodology

How RoofHub roofing data is built.

RoofHub publishes research and planning estimates, not binding quotes. The useful part is not only the number — it is knowing where the number came from and what it includes.

01

Price bases stay separate

Material-only, labour, supply/install and complete reroof figures are never silently blended.

02

Unknown GST stays unknown

An individual source can still be shown with “GST not stated”, but it does not feed a normalised GST-specific RoofHub range.

03

Estimate ≠ quote

Tools support planning. Site conditions and product details still need a contractor to confirm the final scope.

Evidence policy

Three evidence tiers, chosen for the claim being made.

Ten pages repeating one claim are not ten independent sources. Technical claims favour primary evidence; real-world pricing benefits from market evidence.

Tier 1

Primary evidence

New Zealand government/regulators, technical bodies, manufacturers, direct supplier listings and product documentation.

Tier 2

Market evidence

Published contractor/scaffolder pricing, case studies, merchant listings and public project examples.

Tier 3

Editorial evidence

Explanatory articles and experience-based commentary. Useful context, but not treated as independent technical proof.

Provenance

What RoofHub keeps for important observations.

Enough context is stored to re-check a number later and to understand why two apparently similar prices should not be averaged together.

  • Publisher and canonical source URL
  • Source publication/update date where visible
  • RoofHub observation date
  • Unit and price basis
  • GST treatment if stated
  • Region, inclusions and exclusions
  • Evidence tier, confidence and review status

From source to answer

One reviewable pipeline.

  1. 01
    Record the observation

    Raw figures are stored centrally with their source context rather than copied into multiple pages.

  2. 02
    Normalise the meaning

    Material-only, labour-only, supply/install and complete-project observations remain distinct. Units and GST treatment are explicit.

  3. 03
    Compare like with like

    RoofHub uses comparable observations to support indicative ranges and shows broader market spans separately when scopes differ.

  4. 04
    Review and date

    Pricing pages carry a review date. Volatile observations can be marked stale without deleting their provenance.

Range design

Observed market span and RoofHub indicative range are not automatically the same thing.

A single unusual project can widen the raw observed span dramatically. RoofHub therefore preserves the full observations but only publishes a narrower “indicative” range when there is enough comparable evidence and a documented method for deriving it. Until then, pages show the observations themselves instead of manufacturing precision.

Corrections and stronger public sources can be submitted through the contact & corrections form.

Source catalogue

See the types of evidence RoofHub records.

The public sources page explains the source policy and how pricing observations are handled.

View sources policy