If you’ve noticed green patches spreading across your home’s exterior, you’re not alone. Across Auckland, homeowners frequently deal with green staining on weatherboards, cladding, fences, and even roofs.
That “green” isn’t just dirt — it’s usually mould, algae, or lichen growth, and it’s a common issue due to Auckland’s unique climate.
In this guide, we’ll break down:
- What’s causing it
- Why it keeps coming back
- How to remove it properly
- And how to stop it for good
What Is the Green Stuff on Your House?
The green staining you see is typically a combination of:
- Algae – thrives in damp, shaded areas
- Mould – grows on organic material and moisture
- Lichen – a stubborn mix of fungus and algae
These organisms attach themselves to surfaces and feed off moisture, dirt, and airborne particles.
👉 Over time, they spread and become harder to remove.
Why This Happens So Often in Auckland
1. High Humidity and Rainfall
Auckland’s climate creates the perfect breeding ground.
- Frequent rain
- High humidity
- Mild temperatures year-round
👉 These conditions allow mould and algae to grow continuously.
2. Shaded Areas Around Your Home
Homes surrounded by:
- Trees
- Fences
- Neighbouring buildings
…don’t get enough sunlight to dry surfaces.
👉 Damp + shade = rapid green growth
3. Coastal Air and Salt
Many areas across Auckland — especially East and North Shore — are exposed to salt air.
Salt:
- Holds moisture on surfaces
- Accelerates mould and algae growth
4. Dirt and Organic Build-Up
Dust, pollen, and pollution settle on your home’s exterior.
👉 This becomes a food source for mould and algae.
Where You’ll See It First
Green growth usually appears in:
- South-facing walls
- Under eaves and gutters
- Behind downpipes
- Around decks and fences
- On painted weatherboards
- On roofs and tiles
👉 Once it starts, it spreads quickly if untreated.
Is It Just Cosmetic — Or a Real Problem?
Many homeowners ignore it at first… but it can cause real damage:
❌ Paint deterioration
❌ Permanent staining
❌ Rot in timber surfaces
❌ Reduced property value
👉 Left untreated, it becomes more expensive to fix.
Why It Keeps Coming Back
This is the biggest frustration.
Even if you wash it off with water:
👉 It comes back within months
Why?
Because:
- The root system (spores) is still alive
- Water blasting alone doesn’t kill growth
- Moisture conditions remain
The Right Way to Remove It (This Is Key)
❌ High-pressure water blasting (wrong method for houses)
This can:
- Damage paint
- Force water into cladding
- Spread spores
✅ Soft Washing (Correct Method)
Professional Metro Water Blasting uses a low-pressure soft wash system that:
- Applies a specialised cleaning solution
- Kills mould, algae, and lichen at the root
- Gently rinses surfaces without damage
👉 This delivers a long-lasting clean, not just a temporary fix.
How Long Does It Last?
With proper treatment:
- Results typically last 6–12 months (or longer)
- Some homes stay clean even longer depending on conditions
👉 Regular maintenance keeps your home looking fresh year-round.
How to Prevent Green Growth
You can slow it down with a few simple steps:
✔ Trim trees and increase sunlight
✔ Keep gutters clean and flowing
✔ Wash your house regularly
✔ Remove nearby moisture sources
✔ Schedule annual exterior cleaning
When Should You Book a House Wash?
In Auckland, the best times are:
- Autumn → before winter moisture hits
- Spring → remove winter build-up
👉 If your house already looks green, don’t wait.
Related Exterior Issues (Don’t Ignore These)
If your house is turning green, chances are you may also have:
- Roof moss and lichen growth
- Blocked or overflowing gutters
- Slippery driveways or paths
👉 A full exterior clean often gives the best results.
Professional House Washing in Auckland
If you want a safe, effective, and long-lasting solution, professional house washing in Auckland is the best option.
It:
- Restores your home’s appearance
- Protects paint and surfaces
- Prevents long-term damage
Get a Quote Today
If your home is showing signs of mould or algae, now is the time to act.
👉 Visit: https://www.metrowaterblasting.co.nz/house-wash-auckland/
👉 Or call 0800 997 997