Apply the answer
Turn roof lines into measured quantities.
If you already have plans or measurements, keep ridges, hips, valleys, barges and other components separate from roof area.
What are the main roof flashing types?
| Name | Where it is | Main job |
|---|---|---|
| Ridge | High line where two roof planes meet. | Closes and weatherproofs the meeting of the roof planes. Sources: NZ Metal Roofing Manufacturers. |
| Hip | Sloping external line where two roof planes meet. | Weatherproofs the external intersection and covers cut sheet edges. Sources: NZ Metal Roofing Manufacturers. |
| Valley | Internal line where two roof planes drain toward each other. | Receives and carries concentrated roof water while protecting the internal junction. Sources: NZ Metal Roofing Manufacturers. |
| Barge / verge | Sloping outside edge of a gable roof. | Closes and weatherproofs the side edge of the roofing. Sources: NZ Metal Roofing Manufacturers. |
| Apron | Where a roof surface meets an adjacent wall or similar upstand. | Turns water away from the wall/roof junction. Sources: NZ Metal Roofing Manufacturers. |
| Parapet capping | Top of a parapet wall. | Protects the top of the wall from moisture entry. Sources: NZ Metal Roofing Manufacturers. |
Why do flashings change roofing cost and labour?
A simple gable can have a large roof area but relatively few junctions. A smaller cut-up roof can have several valleys, hips, wall junctions and penetrations. Those details require additional measured lengths, cutting, folding, joining and weatherproofing work, so roof area alone does not describe the full scope. Sources: NZ Metal Roofing Manufacturers; BRANZ.
BRANZ roof-junction examples show how several flashing pieces can interact at one junction. This is why RoofHub keeps lineal roof components separate from square metres in the detailed estimator. Sources: BRANZ.
How do roof shapes create ridges, hips and valleys?
- A simple gable normally has a ridge and two barge/verge edges.
- A hip roof adds sloping hip lines and may have a shorter ridge.
- Intersecting gables create valleys where inward-facing planes meet.
- Hip-and-valley roofs combine external hips and internal valleys.
- Dormers and multiple roof sections can add ridges, valleys, aprons, barges and penetration-style junctions.
What should you look for in a quote?
- Are major flashings included or excluded?
- Are valleys and wall/apron junctions identified where the roof has them?
- Are skylights, chimneys, vents and other penetrations included?
- Are replacement gutters/spouting being confused with roof flashings?
- If existing flashings are to be reused, is that assumption explicit?
Can a leaking flashing just be sealed?
Sometimes a local repair is appropriate, but sealant is not a substitute for a correctly designed and installed water-management detail. The defect, material compatibility, lap arrangement and surrounding construction need to be understood first. Sources: NZ Metal Roofing Manufacturers; BRANZ.
Related questions
Is a valley the same thing as a gutter?
No. A roof valley is an internal roof junction that carries concentrated water between roof planes. A gutter or spouting collects water at an eave or other drainage edge and discharges it to outlets/downpipes. Sources: NZ Metal Roofing Manufacturers; Building CodeHub / MBIE.
Is barge the same as verge?
The terms are commonly paired for the flashing at the sloping outside edge of a gable. MRM groups Barge and Verge together as a flashing type. Sources: NZ Metal Roofing Manufacturers.
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.
- primaryNZ Metal Roofing Manufacturers: Code of Practice v26.09: Flashings - Current MRM flashing guidance. Defines the purpose of flashings and identifies common types including ridge/hip, barge/verge, parapet cappings, apron and valley; penetration flashings are treated separately. Page checked 2026-10-21. Publication date not stated. · industry-technical
- primaryBRANZ: Roof junction detail - BRANZ worked detail showing why junctions can require multiple interacting flashings. Used to explain complexity, not as a universal detail for every roof or cladding system. Page checked 2026-10-21. Publication date not stated. · industry-technical
- primaryBuilding CodeHub / MBIE: Acceptable Solution E1/AS1: Surface Water, Amendment 12 (2023-11-02) - Current Building CodeHub record for E1/AS1 Amendment 12. Provides one compliance pathway for disposal of surface water, including roof drainage; project design must use the applicable current compliance route and local rainfall information. 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.
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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.