Should I clean my roof or replace it?

Short answer: For 8 out of 10 Brisbane homes we assess, a professional soft-wash clean and re-seal can add 10-20 years of life to an existing roof at 5-10% of the cost of replacement. Replacement is only genuinely required when the substrate itself has failed.

The Brisbane roof cost gap

Option	Typical price (AUD, standard 4-bed)
Professional soft-wash clean	$449 - $899
Clean + re-seal (tile / terracotta)	$2,500 - $4,500
Full re-roof (Colorbond)	$18,000 - $35,000
Full re-roof (concrete tile)	$22,000 - $40,000

The gap between "clean and re-seal" and "replace" is enormous - and most Brisbane roofs that look "past it" are actually just heavily soiled with lichen, moss and Colorbond oxidation.

When cleaning is the right call

Cleaning wins if your roof shows:

• Black streaking (this is gloeocapsa magma algae - purely cosmetic)
• Green or grey lichen and moss patches
• Faded, chalky Colorbond colour
• Terracotta tiles that have lost their glaze sheen
• Concrete tiles with moss between the ridges

All of the above are surface issues. A soft-wash (never high-pressure on tiles - it strips glaze and breaks tiles) with the right anti-fungal treatment restores 90% of the original appearance and stops further degradation.

When you genuinely need replacement

Replacement is unavoidable if the structure itself has failed:

• Widespread cracked or slipped tiles (more than ~15%)
• Rusted-through Colorbond sheets (not just faded)
• Sagging roof line indicating batten or truss failure
• Persistent internal leaks after multiple repairs
• Terracotta glaze fully worn through exposing raw clay
• Asbestos roofing (should be replaced regardless of condition)

If a roofer is quoting replacement without pointing to at least two of the above, get a second opinion.

The Brisbane climate factor

South East Queensland's combination of humidity, subtropical rain and heat is brutal on roofs. Colorbond fades faster than in cooler climates, and terracotta tiles pick up biological growth on the shaded southern face within 3-5 years. This makes SEQ roofs look older than they are - most look 20 years old at 8 years without cleaning.

Routine cleaning every 3-5 years keeps a roof performing to its full 40-50 year design life.

What a proper Brisbane roof clean includes

• Pre-clean inspection with photos
• Soft-wash with commercial anti-fungal treatment
• Gutter and valley clean-out (any debris knocked down)
• Downpipe flush
• Post-clean photo report
• Optional: colour re-seal for tile roofs

Red flags in a roof cleaning quote

• High-pressure washing on tile or terracotta (breaks tiles, strips glaze)
• No anti-fungal treatment (moss returns in 12 months)
• No gutter or valley clean-out
• No public liability insurance ($10M is the standard)
• No safety gear or harness plan for two-storey work

Need help?

Not sure whether your Brisbane roof needs a clean or genuinely needs replacement? Book a free assessment - we'll tell you honestly which side you're on. Book online or call 0416 737 005.

Primeline Home Group - fully insured, ABN 85 687 853 881, based in Park Ridge South.