Updated 2/26/21
Corten (or COR-TEN) is the most commonly used name for weathering steel. Weathering steel is designed to develop a thin layer of rust that acts as a protective coating. I like to think of it as shou sugi ban for steel.
Corten was developed for practical reasons: to eliminate the need to paint or coat steel. For a landscape designer corten’s primary appeal is aesthetic. The patina the steel acquires is attractive in a way that works so well with stone, wood, and plants.
Here at Ross NW Watergardens we most often use corten steel for pots, planters, troughs, and raised beds. It can also be used for retaining walls, screens, fences, and fire features.
Are you considering corten steel for your landscape design project?
View one of our projects that utilizes corten steel here.
Corten Steel: What You Need To Know:
Is corten steel expensive? Yes, it is. Corten is significantly more expensive than other common grades of steel. Corten steel planters are easily 50%-100% more expensive than a similarly sized planter of another long-lasting material. Custom applications will cost even more, since they need to fabricated and then installed.
It takes time to develop the patina. Some modular corten steel products (like fire pits) may already have the rust coating. Usually, however, they don’t. You will need to wait for it to happen naturally or accelerate it with an acid based product (or some diluted vinegar). During the process surrounding materials can be stained. If you have corten troughs, for example, sitting on a paver patio you will want to lift them by putting something under the edges of the trough so the pavers are not damaged.
Corten steel is long-lasting, but other materials last longer. Depending on the application and location corten steel can last for decades. However, in the Pacific NW you will probably get longer life out of stone and concrete. A juniper wall might even outlast a steel one!
Corten steel is perfect for modern landscapes. The color and texture fits very well with acid washed concrete, aggregates such as decomposed granite, and is the perfect backdrop for grasses and matrix planting schemes.
Corten steel walls are a challenge. The wall will need to be engineered and then installed carefully. Very few companies in the Portland-area have actual experience with them. A simpler solution is to build the wall with wood or concrete and then clad it with steel.
Corten steel can be used in water features. However, this is a custom application and it is difficult to say exactly how long they will last. There are corten steel fountains that can be purchased and installed- but it seems they are made in China and ship from the UK- making them not very practical for our landscape designs.
Your raised garden may be the best use of corten. I like raised beds to be attractive even when they are empty. If you have a rough spring and don’t get your garden beds planted they won’t be an eyesore. Thin edges, like those you get with corten, are great because it means the raised beds themselves are not taking up more space than necessary. Decide your garden is not in the best place? The beds can relocated easily.
Steel edging can utilize corten, but doesn’t need to. We use steel edging all the time: 1/8”x4”x20’ pieces of cold rolled steel. It works great. Corten steel edging is nice, but since the purpose of the edging is to define and edge and then disappear it doesn’t make sense to use it.
Looking to add a touch of corten to your landscape? Need a landscape design and hope to incorporate corten steel? Contact us today for a free landscape design consultation!
Corten Steel Resources:
Corten steel in landscapes on Houzz.
How to use corten steel in the garden via Gardenista.
The definitive guide to using Cor-Ten from Land8.
Using corten steel via Garden Design.
Corten steel in landscapes (PICTURES).
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