You notice it while hanging out the washing. The roof that was a deep charcoal when you bought the place has gone chalky and pale, there are orange freckles along a few of the sheet joins, and after the last big storm a brown ring turned up on the laundry ceiling. The next question is nearly always the same: can a metal roof like this be brought back, or is it time for a new one?
More often than people expect, it can be saved. Colorbond roof restoration is a proper job with a proper sequence, and on the right roof it buys years for a fraction of what a re-roof costs. On the wrong roof it is money spent hiding a problem. Here is how we tell the two apart on Canberra homes, and what the work actually involves.
Metal roofs wear out at the joins, not in the middle of the sheet
The steel sheets themselves are tough. What gives up first is everything that holds them down and seals the gaps: the screws, the small rubber washer under each screw head, the flashings where the roof meets a wall or chimney, and the valleys where two roof slopes meet.
The screws are the big one. That rubber washer is the only thing keeping water out of each hole, and years of sun plus Canberra's swing from frosty nights to hot afternoons cook it until it shrinks and cracks. Water then weeps down the screw and into the roof space. We usually see this start somewhere around the 15 to 25 year mark. You can't see it from the ground, so the first sign is often a stain on a ceiling.
Rust is the other clock. It starts in quiet places: where two sheets overlap, around fixings, along a scratch left by a boot or a dropped tool. Caught while it is still on the surface, it can be treated. Once it is through the coating and into the steel, it only spreads.
Canberra has two kinds of metal roof, and they need different work
Most of the metal roofs we get onto fall into one of two groups, and knowing which one yours belongs to tells you most of what the job will be.
The first is the newer estate roof. Gungahlin, the Molonglo Valley, Googong and Jerrabomberra are full of Colorbond that is structurally fine but lets water in at the details: flashings that were never sealed properly, pipes and vents through the roof without a decent seal, and washers starting to perish. These roofs rarely need a recoat. They need the leak points found and fixed, and sometimes a full re-screw.
The second is the older metal roof, found across the established suburbs and the older parts of Queanbeyan. These are often bare Zincalume (the plain silver steel) or Colorbond that has been painted before. Here the steel itself is ageing, with rust at the laps and a coating that has gone powdery. This is where a restoration in the full sense comes in.
What a proper metal roof restoration involves
The order matters more than the paint. A coating is only ever as good as the surface it goes onto, so most of the work happens before any colour goes on.
- Inspection first. Sheets, laps, screws, flashings, valleys and gutters all get checked, along with the roof space for water marks, and photographed so you can see what we saw.
- A thorough clean. Dirt, lichen and chalky old coating come off so the primer has something solid to grip.
- Screws replaced. Perished or rusted fasteners are swapped out. Once a few washers have failed, the rest usually aren't far behind, so it is often the whole roof.
- Rust treated or cut out. Surface rust is cleaned back, treated and primed. A sheet or flashing that has rusted through gets replaced rather than painted over.
- Flashings and valleys sorted. Resealed where they are sound, renewed where they are not.
- Primer, then two top coats. Older or previously painted Colorbond needs the right etch and primer so the new coating bonds, instead of peeling off in sheets a year later.
Skipping steps to hit a lower price is exactly how metal roof coatings fail. Paint over active rust and you seal the rust in, where it keeps working and eventually lifts the new coat. Paint over perished screws and the roof still leaks. It just looks better while it does.
This sequence is the everyday work of our Colorbond and metal roofing team, and most jobs turn out to be a mix of re-screwing, flashing repairs and rust treatment rather than one big fix.
The coat of paint is the last step, not the whole job
Plenty of people start out searching for metal roof painting, and fair enough: a fresh coating restores the colour and adds a layer of protection against the weather. Metal is also simpler to coat than tile because there is no ridge mortar to rebed or repoint, which is why it usually works out cheaper per square metre. Charcoal tones like Monument, Basalt and Woodland Grey are the popular picks on Canberra streets at the moment, though the full range is available.
Timing matters too. Coatings need dry, mild days to cure and bond properly, so we plan around the frostiest weeks of a Canberra winter. Done properly on a sound roof, a good coating lasts ten years or more. If the paint side is what you are weighing up, our breakdown of what a roof coating job typically costs in Canberra explains how those quotes are put together.
When the steel is too far gone, a recoat is the wrong spend
Restoration works while the rust is on the surface. Once the steel has rusted right through, no coating will hold it together. A few holed sheets can be replaced on their own, but if the rust is through in many places, a new roof becomes the honest answer.
The signs we look for are rust flaking off in layers, pinholes of daylight visible from inside the roof space, sheets that feel soft or crumble at the edges, and heavy rust along most of the laps rather than a few. Another one that catches people out: some older Canberra metal roofs have no sarking (the foil layer under the sheets), and on frosty nights condensation forms on the cold underside of the steel and drips like a leak. A recoat does nothing for that. A re-roof is the chance to add sarking and insulation properly.
If yours is heading that way, it is worth reading up on what sets the price of a full re-roof before you start comparing quotes. We would much rather tell you a roof has another ten years in it with new screws and some rust treatment than sell you a new one it doesn't need. The reverse is true too: we won't coat a roof that is past saving.
A few things worth noting before anyone climbs up
You don't need to get on the roof to give a roofer a head start. From the yard, with your phone zoomed in, look for:
- chalky, faded colour, worst on the north and west faces
- orange spots at the sheet overlaps or around screw heads
- rust stains running into the gutters
- water marks on ceilings, especially near walls or vents
- whether the roof has had any work done before, and roughly when
None of that replaces an inspection, but it helps us tell you on the first visit which group your roof is in and how far along it is.
Find out which stage your roof is at
We are ACT licensed roof plumbers (Licence 242220C) based in Giralang, and we look at metal roofs across Canberra and Queanbeyan every week. An inspection is free and comes with a photo report, and any work is priced as a fixed written quote. Our coating system carries a 15-year warranty on selected services (conditions apply). If your Colorbond is fading, rusting or leaking, book a look at your metal roof or call us on (02) 6109 5008.