Choosing between longrun metal roofing and concrete or clay tiles is one of the most significant decisions you'll make when building or re-roofing a New Zealand home. Both systems have proven track records in NZ conditions, but they suit different climates, budgets, and structural situations. This guide walks you through everything you need to weigh up before committing.
What Is Longrun Roofing?
Longrun roofing (also called metal roofing or corrugate/tray roofing) is made from steel or aluminium roll-formed into continuous lengths — often running from ridge to gutter in a single sheet. Common profiles include corrugate, trimdek, standing seam, and concealed-fix trays. Most NZ longrun steel is Zincalume or Colorsteel (a pre-painted Zincalume product), supplied by manufacturers such as NZ Steel. It is lightweight, fast to install, and widely used on both residential and commercial buildings throughout New Zealand.
What Is Tile Roofing?
Roof tiles in NZ are most commonly concrete tiles (e.g. Monier or Decra) or clay tiles. They are individual units laid in overlapping courses over battens. Tiles give a traditional, textured appearance and have excellent thermal mass. However, they are significantly heavier than metal roofing and require a roof structure engineered to carry that load — an important consideration under NZS 3604 timber framing rules and NZ Building Code clause B1 (Structure).
Key Differences at a Glance
| Factor | Longrun Metal | Concrete/Clay Tile |
|---|---|---|
| Weight | ~4–7 kg/m² | ~40–55 kg/m² |
| Minimum pitch | As low as 3° (profile-dependent) | Typically 15–25°+ |
| Lifespan | 40–70+ years (quality steel) | 50+ years (concrete); 100+ (clay) |
| Maintenance | Low — clear gutters, check flashings | Moderate — replace cracked tiles, repoint ridge |
| Noise (rain) | Higher without insulation underlay | Lower — tiles absorb sound |
| Thermal mass | Low | High |
| Recyclability | Steel is fully recyclable | Limited |
| Typical NZ use | New builds, re-roofs, rural, coastal | Established suburbs, heritage, high-pitch roofs |
How NZ Climate Affects Your Choice
New Zealand's climate varies dramatically, and your region should heavily influence your decision.
- Northland/Auckland/Bay of Plenty: High humidity and UV exposure. Both materials perform well, but ensure metal roofing carries a suitable coastal warranty — standard Colorsteel may not be warranted within 100–500 m of the sea. Zincalume Coastal or Colorsteel Maxx are better options near salt air.
- Wellington/Cook Strait corridor: Extreme wind loads. Longrun metal must be fixed to manufacturer specifications for high-wind zones; concealed-fix profiles reduce wind-uplift risk. Tiles must be mechanically fixed (not just nailed) in high-wind areas.
- Canterbury/Otago/Southland: Freeze-thaw cycles can crack concrete tiles over time. Metal roofing handles frost well. Snow loads must be considered under B1 structural requirements.
- West Coast: Very high rainfall. Both systems cope, but ensuring correct E1 (surface water) and E2 (external moisture) compliance with quality underlays and flashings is critical regardless of material.
What Affects the Cost of Each System?
Neither material has a single fixed price — costs depend on a range of factors. Always get multiple written quotes from qualified roofers before committing.
Cost drivers for longrun metal:
- Profile choice (corrugate is generally more affordable than standing seam)
- Steel grade and coating (standard vs. coastal-rated)
- Roof complexity (hips, valleys, penetrations)
- Underlay and insulation specification
- Removal and disposal of existing roofing
Cost drivers for tile roofing:
- Tile type (concrete is generally less expensive than clay)
- Structural upgrades needed to carry tile weight (can be significant on older homes)
- Batten replacement
- Ridge and hip capping, mortar, and pointing
- Scaffolding (tiles take longer to install, increasing labour time)
As a general principle, longrun metal is often less expensive to supply and install per square metre than concrete tile, and considerably less than clay tile — but always confirm current pricing with your roofing contractor and suppliers such as Bunnings, Mitre 10, or PlaceMakers. Get at least three written quotes and include a contingency in your budget for unexpected structural findings.
Durability and Maintenance
Longrun metal requires relatively little maintenance. Key tasks include keeping gutters and valleys clear of debris, checking and resealing flashings every 5–10 years, and touching up any paint chips promptly to prevent corrosion. Quality Colorsteel products carry manufacturer warranties — check the specific warranty document for your product and location.
Tile roofing is durable but does need periodic attention. Cracked or slipped tiles should be replaced promptly to prevent water ingress. Ridge capping mortar typically needs repointing every 15–25 years. Moss and lichen growth (common in damp NZ climates) should be treated with appropriate biocide wash rather than high-pressure water blasting, which can damage tile surfaces.
BRANZ publishes research on roofing durability and moisture performance that is worth consulting when specifying your system.
Insulation and Energy Efficiency
Under NZ Building Code clause H1 (Energy Efficiency), your roof assembly must meet minimum insulation R-values — these vary by climate zone. Metal roofing on its own has very little thermal resistance, so a quality underlay and ceiling insulation are essential. Tiles provide some thermal mass but still require ceiling insulation to meet H1. For guidance on insulation options, Energywise is a useful resource.
Building Consent and Compliance
Re-roofing an existing home like-for-like (same material, same profile) is generally a Schedule 1 exemption under the Building Act and may not require a building consent — but always confirm with your local council before starting work, as exemptions have conditions and councils interpret them differently. Changing from tiles to metal (or vice versa) may require consent, particularly if structural changes are needed. New builds always require consent.
Flashings around penetrations (chimneys, skylights, pipes) must comply with E2 (External Moisture) requirements. Poor flashing is the leading cause of roofing-related weathertightness failures in NZ.
When to Call a Professional
Roofing work is physically demanding and carries serious fall risks. WorkSafe NZ requires that work at height follows safe work practices — for most homeowners, roof work should be left to qualified tradespeople. A professional roofer will:
- Assess your existing structure for load capacity (critical when moving to tiles)
- Specify the correct underlay, fixings, and flashings for your climate zone
- Ensure compliance with NZ Building Code clauses B1, B2, E1, and E2
- Provide a warranty on workmanship
- Manage scaffolding and health and safety requirements
Look for roofers who are members of the Roofing Association of New Zealand (RANZ) and, where consent work is involved, check that your contractor holds the appropriate Licensed Building Practitioner (LBP) licence. You can find qualified local roofers through tradedirectory.co.nz.
Practical Tips for Getting Good Value
- Get at least three written quotes — itemised so you can compare materials, labour, and disposal separately.
- Check references and past work — ask to see examples of similar roofs in your area.
- Confirm warranties — both product (manufacturer) and workmanship (contractor).
- Plan for contingency — budget an additional 10–15% for unexpected findings such as rotten sarking or purlins.
- Time your project — roofing is best done in settled weather; avoid scheduling during peak storm seasons.
- Consider the long game — a slightly higher upfront cost for a better-grade steel or quality clay tile can mean significantly lower lifetime maintenance costs.
Roofing Association of NZ (RANZ)
Licensed Building Practitioner (LBP)
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