Where rust starts on a garage door
Salt is the obvious cause, but not the only one. Steel-Line's coastal care article says salt water, sand and even sunscreen can corrode a garage door, and that rust most often turns up on the hinges, springs and tracks. It also says homes many kilometres from the beach can still find corrosion coming on faster than they expect.
The parts rain never reaches are the other weak spot. BlueScope's TB-4 bulletin names garage doors among the unwashed areas that need regular cleaning. B&D's warranty brochure lists a lack of rain washing among the things that shorten a door's life, including a door under an eave, canopy, patio, carport or verandah that reaches more than 600mm out from the wall.
Fading, marks or rust?
Not every change in a door's finish is rust. B&D says it is normal for a door's surface to fade or lose gloss over time. The Australian Garage Door Association's inspection guide judges surfaces from a normal viewing position at least 2m away in daylight, and says slight variations in colour and finish are not generally a defect.
Rust that grows, bubbles under the coating or flakes off the hardware is a different story, and worth showing a door specialist before it spreads.
How to wash a garage door
Keep water off the opener
B&D warns not to wash the automatic opener, because it could void the warranty and cause electrocution. Merlin says water can do irreversible damage to the opener motor.
Start with fresh water
BlueScope says a garage door can be hosed with fresh water when you wash the car. Spend longer on the top of the door, the part BlueScope singles out because rain does not rinse it.
Mild soap for dirt that stays
If water alone does not shift it, BlueScope suggests pure soap or a non-abrasive dishwashing detergent in warm water, on a sponge, soft cloth or soft nylon brush.
Rinse it all away
BlueScope's last step is to rinse the door thoroughly once the dirt is off.
Leave out the harsh stuff
BlueScope says never to use abrasive or solvent-based cleaners such as turpentine, petrol, kerosene or paint thinners on its pre-painted steel, and does not recommend hard, mineral rich bore water. The mineral turps some makers suggest for guide tracks stays on the tracks, never the painted face. Keep sunscreen off the coating too, Steel-Line says.
How often to wash a garage door
| How often | More often when | |
|---|---|---|
| BlueScope (TB-4, October 2026) | Six monthly as a minimum | Three monthly where marine salt spray is common, or with a lot of airborne dust or industrial fallout |
| B&D (Australian care sheet) | Every 14 days, with clean water and a soft brush or cloth | Near salt water or industrial fallout |
| Steel-Line | At least every six months, with clean water and a cloth | In salty or industrial areas |
Why washing is a warranty matter too
Grime left on a door can cost you the cover. Steel-Line's warranty excludes damage from grime, chemicals and pollutants that were never cleaned off, and Steel-Line's sectional door manual asks for the panels to be washed regularly to remove corrosive salt and dirt.
Garage doors near the coast
Each maker draws its own line near the sea, and each line means something different. They are not one rule and they don't average out, so read the one for the maker of your door.
Coastal limits, maker by maker
| Distance it names | What it means | |
|---|---|---|
| B&D | Within 1 km of marine, industrial or other corrosive environments | Its warranty brochure says prolonged exposure like this affects a door's life expectancy |
| Steel-Line | Within 800 metres of the sea, or of water at least as salty | Its residential door warranty excludes these installs |
| Gliderol | Within 800 metres of a high salt concentration | Its 7 year corrosion warranty on the curtain of A, AA and B Series roller doors does not apply |
| Steel-Line Coastal Upgrade Pack | Within 1,500 metres of the ocean or any body of salt water | The distance Steel-Line gives for offering its coastal pack |
Coastal hardware
Steel-Line's coastal pack swaps in marine grade powdercoated tracks, brackets and hardware (in Monument only), a nylon brush seal and G316 marine grade stainless steel cables. On the B&D side, its Panelift Icon sectional door has corrosion resistant stainless steel cables. If your door is due for parts near the sea, ask the door specialist what a coastal option would change.
How salty is your spot?
BlueScope's TB-35 bulletin sorts salt marine areas into three classes: surf (breaking surf and ocean spray), exposed (open salt or brackish water with onshore winds but not usually breaking surf) and calm (protected water such as ports, harbours, bays and river estuaries). It calls them a guide only, because prevailing winds, shelter, height above the water and unwashed areas all change how corrosive a site is.
Its examples show that being near water is only part of the story. Manly and Bondi beaches are surf, while Darling Harbour and the Parramatta River are calm. Port Phillip Bay from Altona to Portsea is exposed, and the Yarra at Docklands is calm. Gold Coast beaches are surf and its canal estates calm, and in Perth, Cottesloe is surf while the Swan River west of the Narrows Bridge is calm. These are BlueScope's classes for salt marine areas, not a garage door rule.
Can you fix rust on a garage door?
On the panels or curtain, ask before you paint. B&D's Series 1 manual says touch-up paint is available from a dealer, while BlueScope does not recommend touch-up paint on COLORBOND steel, because the factory finish weathers differently from air-drying paint and touched-up patches can end up looking blotchy. Ask the maker or dealer for your door, and ask what painting would do to the coating warranty.
On the moving parts, don't paint at all. Steel-Line's sectional manual says never to paint the tracks, rollers, hinges, lift cables, springs or locks. Rust on those is a repair, and the door specialist can tell you whether a part can stay or has to go.
If rust has gone right through the curtain or a panel, a new section or a new door may be the better answer. See panels and dents and garage door replacement.
Rusty springs and cables are never a home job
Steel-Line says the lift cables on a sectional door carry its full weight, must be free of frayed or broken strands, and should be replaced only by experienced door personnel. It also warns never to loosen any fastener on the spring assembly or the bottom cable fixtures. If you see rust on a spring, a cable or its fixings, look from a distance, take a photo and leave it to a door specialist.
Lubricant and rust on the moving parts
B&D's maintenance advice is to check the tracks on both sides for debris, leaves and rust, and to make sure they are not bent or out of line. For coastal homes, Steel-Line's advice is to lubricate the door at least twice a year, and every three months for the longest life.
Use the lubricant your door's own manual names. Makers disagree about sprays, and none of the roller garage door advice we read allows grease or oil in the guide tracks. The lubricant guide goes maker by maker.
What to tell the door specialist
- Where the rust is: panels or curtain, bottom rail, tracks, hinges, springs or cables
- Roughly how far you are from the sea, a salt water bay or an estuary
- Whether the door sits under an eave, carport or verandah
- The make and model, and when the door went in, for the warranty
- Photos taken from a safe distance
- Whether the door has started to stick, drag or get noisy
What you can do, and what to leave
You can
- Wash the door the way BlueScope sets out
- Keep sunscreen and harsh cleaners off the coating
- Look over the tracks and hinges for rust and bends
- Photograph the rust and keep the warranty papers handy
Leave to a door specialist
- Rusted springs, cables and their fixings
- Swapping corroded tracks, hinges or rollers
- A new panel or curtain
- Coastal hardware when parts are replaced
What we would do
Photograph the rust today, wash the door the way BlueScope describes, and take the same photo a few months later. Marks that washed off or stayed the same are a cleaning job. Rust that has spread on the tracks, hinges or bottom rail is a repair, and the two photos show the door specialist how fast it is moving.