How to make a metal roof look new again — without replacing it, wrecking it, or wasting cash on gimmicks that don’t work. We’ll walk you through the tools, the process, the warning signs, and the big cleaning myths we bust on the job every other week.
If your metal roof’s looking worse for wear, you’re not alone. We’ve worked on everything from rusting old sheds to faded Colorbond roofs that haven’t seen a wash since the Howard years. But with the right approach — and none of the dodgy shortcuts — you can restore that surface without tearing off sheets or blowing the paint clean off with a water blaster.
The Silent Killer of Street Appeal
Seen your roof go from shiny to flat and patchy? That’s metal roof fading. It’s not just an aesthetic issue — it’s a warning sign. Fading means the protective coatings are breaking down and the metal roof surface is exposed to rust, UV and water damage. Left unchecked you’ll go from discolouration and chalky residue to full-blown deterioration quicker than you think.
Common issues include:
- UV damage (bloody brutal up north and inland)
- Metal roof chalking
- Surface rust and rust spots
- Severe rust stains and spore deposits
- Salt exposure in coastal areas
- Harsh or abrasive detergent use
- Inadequate surface preparation from previous owners
- Age and poor quality or flaking paint jobs
- Acid rain or bore water stains (yep, they’re a real thing)
If the roof material is still structurally sound a metal roof restoration is usually a better option than full replacement. Let’s get into the fixes.
Restoring Roofs, Step by Step
Step 1: Power Wash
Before you even think about painting, get that exterior surface clean. We’re talking a proper power wash — not a garden hose.
- Use power washers with medium to high PSI (around 3000 is the sweet spot for metal surfaces).
- Always rinse downwards to avoid pushing water under metal panels.
- Use clean water or a mixture of water and mild detergent — laundry detergent will do in a pinch.
- Watch out for rust patches — they’re a sign you’ll need rust inhibitor or treatment too.
- In humid areas like QLD or the Top End, moss, algae and lichen are common. Use cleaning solutions designed for metal roof cleaning to lift organic muck without damaging the roof color or surrounding plants.
Step 2: Apply Metal Roof Primer
Once she’s dry, you’re ready for primer. Don’t cut corners here — proper preparation with a metal roof primer is what helps paint stick and protects the bare metal.
- Use rust-inhibiting primers for galvalume metal roof or aluminum siding.
- Apply with airless spray rigs or a high-quality brush.
- Focus on adhesion between panels, joins, edges and fasteners.
- Let it dry properly — don’t rush.
This step ensures excellent adhesion and protection against rain, wind and sun.
Step 3: Paint Your Metal Roof
Now we’re talking. Time to bring back that visual appeal and kerb appeal.
- Choose a good quality paint like acrylic latex paint or alkyd paint. Paint companies like Dulux, Wattyl and Nutech have options for Aussie conditions.
- Popular choice? Light roof colours for cool roof coatings and energy savings.
- Two coats minimum — a layer of paint will only last if applied properly.
- Use acrylic or oil-based paints for your metal roof painting project.
- Apply with airless spray equipment or an airless paint machine for a professional finish.
- Don’t paint in full sun or before a storm — paint thinners and bad timing can cause bubbling or peeling.
- If you’re after reflective coatings or darker colours, check the coating type compatibility.
Step 4: Touch-Ups and Rust Treatment or minor damage? Don’t miss this out.
- Use a wire brush to remove rust and apply rust inhibitor or rust converter.
- Paint where needed after the spray process.
- Replace bad screws with coated ones.
- For flaking paint or stubborn areas use safe paint removers to strip it back.
Tips for Painted Roof
Once your roof’s looking sweet as, you want to keep it that way, but go too hard with metal roof cleaning and you’ll bugger the finish.
Here’s the go:
- Soft bristle brush or sponge mop
- Cold or lukewarm water
- Mild detergent, no harsh acids or chemicals
- Rinse thoroughly to prevent water stains or streaks
- Don’t pressure wash for at least a few months post-paint
If you’re in a commercial building or working with older construction, take extra safety precautions and wear the right gear.
Best Tools
There’s a ton of tools out there, but these are the ones we use:
- Soft-bristle extendable brushes: For a clean surface without damage
- Airless sprayer: For large metal roof restorations
- Roof ladder, harness, safety gear: For steep roof pitch or secondary roof access
- Low-pressure hose with wide spray tip
- Bucket-on-a-rope: Classic tradie trick, works on tall metal buildings
Best Cleaning Products
You want products that get the job done without voiding your roof warranties or killing the garden.
- Wet & Forget Roof Cleaner: Easy on painted surfaces, great for spore deposits
- Nutech RoofWash: Aussie-made, gentle on protective coatings
- Selleys Roof & Gutter Cleaner: Reliable, biodegradable
- Biodegradable degreasers: For oily build-up and aged metal siding
Avoid anything with bleach — it might kill the mould, but it also weakens the paint and kills plant life.
Maintenance Tips
Like any surface exposed to the elements, regular maintenance is key to longevity and looks.
Here’s the checklist property owners should follow:
- Clean the roof every 6–12 months
- Check for rust spots and chalky residue after a wet season or storm damage
- Clear gutters to prevent water pooling
- Repaint every 8–12 years
- Keep trees trimmed — leaves trap moisture
- Inspect flashing and screws before fire season
Maintain it well and your metal siding or roof will outlast a dodgy concrete tile roof any day.
When to Call in a Professional
We love a good DIY, but some jobs are best left to professional roof cleaning services:
- Your roof pitch is steep or hard to access
- There are signs of damage or oil canning
- You’ve got an older or green metal roof with special coatings
- You want that original finish or a paint match from expert roofing contractors
- You’re unsure about the coating type or the energy costs and benefits
Window Cleaning Melbourne Crew also knows that a great-looking roof goes hand in hand with streak-free windows — it’s all part of that top-to-bottom street appeal.
FAQ
Can I use power washers on a metal roof?
Yes — but use caution. Avoid seams, stick to medium pressure, and wear eye protection.
How long does a painted metal roof last?
10–15 years or more with proper maintenance and the right type of paints.
What’s the best paint for metal roofs in Australia?
Acrylic-latex solutions from trusted paint companies are suited to harsh Aussie weather.
Is metal roof restoration cheaper than replacement?
Absolutely. A restoration can be a fraction of the cost of a complete roof replacement.
Can I paint over rust on a metal roof?
Only after removing surface rust and treating with a rust inhibitor. Otherwise, the paint won’t stick and will fail fast.