Corten steel has become one of my most popular finishes for house numbers, address signs and outdoor art, but a lot of people aren't quite sure what it actually is or how it changes once it's up. Here's how I explain it to customers, so you know exactly what to expect before you choose it.
Corten, also called weathering steel, is a steel made to rust in a controlled way. Where ordinary steel just keeps corroding, corten forms a stable rust-like surface that slows further corrosion and gives it that warm, earthy colour. That's why it works so well outdoors, in gardens, entryways and on exterior walls.
It starts as raw grey steel and gradually settles into a rich burnt-orange, deepening to brown over time. The finish evens out and darkens as it goes, and every piece weathers a little differently depending on where it lives, which is part of the charm. The surface is the finish, so unlike paint there's nothing to chip or peel.
Here in New Zealand and Australia corten usually starts changing within a few weeks. Full patina takes roughly one to three months in wetter or coastal spots, and three to six months in drier areas. While it's settling you'll see the colour shift, a bit of temporary runoff, and some variation in tone. That's all normal.
While the patina is forming, corten can run a little, and that runoff can stain a light surface like concrete or plaster underneath it. It's easy to work around. Try not to hang it directly above a pale surface while it's weathering, leave a bit of space off the wall if you can, or weather the piece off the wall first before you mount it. Once it's fully settled the runoff drops right off.
It comes down to the look you're after. Choose corten if you want something warm and natural that changes over time and contrasts beautifully against greenery, timber or a light wall. Choose black or powder-coated steel if you'd rather a crisp, consistent colour that stays exactly as it started. Both last outdoors, so it's really an aesthetic call. One thing I'll always mention: corten should be left in its natural form, never powder coated, because it keeps rusting under a coating and eventually lifts it.
Corten looks its best in garden settings, alongside timber or stone, and on modern coastal or rural homes. It pairs naturally with greenery, concrete and timber cladding, which is why it's such a favourite for entryways with a bit of landscaping.
If you're considering it, have a look at my corten house numbers and address signs and my corten wall art and garden pieces, all made for New Zealand and Australian conditions. If you're not sure it's right for your spot, just ask.
It usually starts within a few weeks. Full patina takes about one to three months in wetter or coastal areas, and three to six months somewhere dry.
A little, while the patina is forming. That early runoff can mark a pale surface below it, so avoid hanging it straight above light concrete or plaster at first, or weather the piece off the wall before mounting. Once settled, the runoff drops away.
Yes. It weathers a bit faster and darker by the sea, and in very exposed salt spots the surface stays a little more active, but plenty of coastal homes choose it for the natural look.
No. It keeps rusting underneath the coating, which eventually traps moisture and lifts the finish. Corten is best left raw to weather naturally.
Very. It's strong, made for long-term outdoor use, and because the rust surface is the finish there's nothing to chip or repaint. It just looks after itself.
Corten for a warm, natural finish that changes over time, black powder-coat for a crisp colour that stays put. Both are durable, so choose on the look you want.
Yes, I make house numbers, address signs and outdoor art in corten, all designed and cut in Auckland for NZ and Australian conditions.
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Sheryl
May 16, 2026
Hi there. Is the three albatross birds that you sell in “corten steel” also available in powder coated steel? If yes, what colours are available & what is the cost please? Thank you. Sheryl W