Roof age and solar panels in Perth: when to re-roof before or after installing solar

Solar panels are warranted for 25 years. Most Perth roofs last 20–35+ years depending on material and maintenance. If you install solar on a roof that needs significant work within 10 years, you'll face the cost of removing and reinstalling the solar system when that roof work happens.

Expected roof lifespans in Perth

Terracotta/concrete tile (most common in Perth): Tiles: 40–60 years. Bedding and pointing (the mortar that holds ridge capping and bedding): 20–35 years. Most Perth tile roof failures involve the bedding/pointing rather than the tiles themselves. A professionally re-bedded roof can have another 20–25 years of life.

Colorbond or Zincalume steel (common in newer homes): Colorbond steel has a 25-year warranty and practical lifespan of 30–50 years in Perth conditions. Minimal maintenance required other than periodic cleaning. Generally very compatible with solar installation.

Corrugated asbestos cement (pre-1987 homes): Some older Perth homes still have asbestos cement roofing (fibrous cement corrugated sheeting, "super-six"). This material is stable when intact but friable when cut or drilled. Solar installation on an asbestos cement roof requires licensed asbestos contractors and additional costs. Many owners choose to re-roof before installing solar.

Concrete flat roof (some commercial-scale residential, granny flats): Flat roofs use waterproofing membranes with 15–25 year lifespans. Solar installation on flat roofs uses ballasted mounting systems (no penetrations), making solar removal for membrane replacement straightforward.

Cost of removing and reinstalling solar for roof work

If your roof needs significant work after solar is installed, the solar system must be temporarily removed:

Typical solar removal and reinstallation cost (6.6kW system):

• Labour for de-installation: $800–$1,500
• Safe storage during roof work: $0 (usually stored on site)
• Reinstallation: $1,000–$2,000
• Testing and recommissioning: $200–$400
• Total: approximately $2,000–$4,000

This cost applies whenever:

• Replacing roof tiles
• Re-bedding and pointing a tile roof
• Full roof replacement (any material)
• Repairing roof leaks under panel locations

How to assess your roof before getting solar quotes

Signs a tile roof needs work soon:

• Cracked, broken, or missing tiles visible from ground
• Visible mortar deterioration around ridge capping
• Loose ridge caps (can be seen from ground with binoculars, or after wind events when cap movement is apparent)
• Age > 20 years with no previous re-bed/point work
• Staining or moss growth (indicates moisture retention, which accelerates tile and bedding degradation)

Signs a steel roof may need attention:

• Visible rust spots or coating failure (especially along seams, around fixings)
• Damaged corrugations or panels from storm, hail, or impact
• Age > 30 years without inspection

Professional roof inspection: A licensed roofing inspector can assess remaining life and identify whether work is needed before solar. Cost: approximately $200–$500. If the inspector finds significant work is required within 5–7 years, scheduling that before solar installation avoids the future re-installation cost.

The decision framework: re-roof first or solar first?

Re-roof first if:

• Your roof has clear signs of needing work within 5–7 years
• Your roof is a pre-1987 asbestos cement type
• The re-roofing cost difference (with vs without solar removal) is significant

Solar first if:

• Your roof is Colorbond or newer (post-2000) tile in good condition
• The roof has been re-pointed within the past 10–15 years
• You've had a professional inspection and received a "good condition" assessment

Do both simultaneously: Some Perth households co-ordinate a partial tile re-roof (ridge capping, bedding repair) with the solar installation appointment, using the same roofing contractor for the structural work and the solar installer for panels and electrical. This eliminates future reinstallation costs.

Tile types and solar compatibility

Terracotta tiles: Most common for older Perth homes (1970s–1990s). Durable when intact. Solar mounting rails attach to roof battens beneath tiles using custom tile brackets that hook under adjacent tiles. Penetrations are sealed. Well-suited for solar once the bedding is confirmed sound.

Concrete tiles: Common in 1990s–2000s Perth homes. Similar to terracotta in mounting approach. Generally in better condition than older terracotta.

Decramastic (pressed steel) tiles: Less common. Special mounting hardware required. Some installers charge extra for decramastic roofs.

Flat profile tiles: Good solar mounting compatibility — flatter profile allows cleaner rail runs.

High-profile (barrel/Roman) tiles: More complex installation — brackets must accommodate higher profile. Some installers charge a premium.

Warranties and roof penetrations

Solar mounting requires drilling through the roof cladding into roof battens/rafters. This creates penetrations that are sealed with weatherproof mastic/sealant:

• Good quality sealed penetrations should last 10+ years
• If a tile roof is re-bedded after solar installation, the sealant is typically re-done as part of the roofing work
• If you sell the home, the Certificate of Compliance (electrical) documents the installation — new owners should be aware of penetrations

Most solar installation workmanship warranties (5 years) cover roof penetration waterproofing during the warranty period.

Before getting solar quotes, examine your roof from ground level or arrange an inspection if you have any concerns. A $300 roof inspection before a $6,000 solar installation is worthwhile if your roof is more than 20 years old and hasn't been assessed recently.