Moss on a colorbond roof is more than cosmetic — it traps moisture that accelerates corrosion and paint degradation. And pressure washing makes it worse by stripping the protective coating. Soft washing is the safe solution.
We reply within 2 hours · Mon–Sat
Colorbond steel roofing is Australia's most popular roofing material for good reason — it's durable, low-maintenance and performs well in Queensland's climate. But colorbond roofs are not immune to biological growth. Moss, algae and lichen can establish on colorbond in shaded, coastal or humid positions, and when they do the risks are different to tile roofs. Moss and algae trap moisture against the colorbond surface. In Queensland's coastal environment — particularly around Redlands, Moreton Bay and the Gold Coast — this moisture combines with salt air to accelerate paint degradation and, eventually, corrosion of the steel beneath. Critically, high-pressure washing on colorbond strips the factory-applied paint coating, exposing bare metal and voiding manufacturer warranties. Soft washing is the only appropriate cleaning method for colorbond roofs.
Despite colorbond's smooth surface, moss and algae can establish in positions where the roof stays damp — typically shaded by trees, in south-facing aspects, or in coastal environments where salt air and constant humidity create ideal growing conditions. Once established, the growth retains moisture against the surface which is exactly the environment that accelerates further growth.
High-pressure washing on colorbond is a genuine risk. The factory-applied Colorbond paint system is designed for weather resistance, not pressure. Pressure washing can strip the paint coating, leave pressure marks, and expose the Zincalume steel substrate to moisture — the very problem you're trying to prevent. Most colorbond manufacturers explicitly advise against high-pressure washing.
Soft washing uses a pH-balanced cleaning solution applied at very low pressure — typically 50 to 100psi, compared to 3,000 to 4,000psi for pressure washing. The chemical solution kills moss and algae at the root without any mechanical force on the coating. The roof is rinsed at low pressure, leaving the colorbond paint system completely intact.
Colorbond roofs in coastal positions around Redlands, Moreton Bay and the Gold Coast face the additional challenge of salt air deposits. Salt combined with biological growth creates an acidic environment on the roof surface that accelerates paint degradation. Regular soft washing removes both the biological growth and salt deposits, extending the life of the coating significantly.
No — this is strongly advised against. High-pressure washing strips the factory-applied paint coating from colorbond roofing, voids manufacturer warranties and exposes the steel substrate to corrosion. Soft washing at low pressure is the correct and only safe method.
Yes, over time. Moss and algae trap moisture against the colorbond surface, and in coastal environments that moisture combined with salt accelerates paint degradation and eventually corrosion. Regular soft washing prevents this damage.
Every 12 to 24 months is typical for most SEQ positions. Coastal properties near Redlands, Moreton Bay and the Gold Coast may benefit from annual cleaning due to salt air exposure. Properties in heavily shaded positions also tend to need more frequent attention.
No — soft washing at low pressure with appropriate pH-balanced solutions is consistent with colorbond manufacturer care guidelines. High-pressure washing is what voids warranties.
Serving Redlands and all of South East Queensland. We reply within 2 hours, Mon–Sat.
0412 291 614