Designer Robert Jackson chose our Corten steel troughs to construct a stylish planter bench for a roof terrace. We ask him how and show you the result.

European larch fence, bench and decking with 2 Corten Steel rectangular planters
Our Corten steel trough offered the ideal dimensions for creating this planter bench seat by Robert Jackson.

A roof terrace in East Dulwich, London, offered Robert the chance to create a simple, practical construction with real presence, thanks to the materials used. Part of a larger project, the terrace added additional outdoor space with plenty of room for mingling and entertaining.

Planter bench construction

The way the bench floats between the two rectangular planters makes you wonder for a moment if it’s cantilevered off the fence.

“No,” laughs Robert, who drilled holes in the planters to accommodate bolts. “If you imagine two pieces of 2x4 timber, one on the outside and one on the inside of the planter, bolted together through the steel… In practice, the timber frame of the bench—which you don’t see across the front, back and between the ends—formed the outside piece that I drilled through.”

Using planters like these means there is plenty of weight in them, once the soil goes in. This makes the construction very stable. "The planters can easily take a good span of bench," says Robert. "The key is to use nuts and bolts and have timber on the inside of the planter, so this braces the seating."

Choice of materials

Robert chose our Corten Steel Tall Trough Planters for their narrow dimensions. These fit perfectly with a good width of seating. “They also had to be tall enough to accommodate the bench and planting at the right height.”

But he also delights in the material. “I love the contrast between timber and Corten steel,” he says. “I had cool clients who appreciated the design and like the idea that the steel will change over time.”

The bench seat is made from European larch to match the slatted fence and decking.

Two Corten steel trough planters provide sturdy support for a bench fixed between them against slatted fence on roof terrace.
Robert, who runs Robert Jackson Gardens, chose airy plants such as achillea and Verbena bonariensis 'Lollipop' to add height and contrast.

Filling the planters

As with any roof terrace or balcony, the weight of the finished bench had to be considered. So, the bottom third of each rectangular metal trough planter is filled with Leca, a very lightweight aggregate made up of expanded clay balls.

Leca is a porous growing medium, which is ideal for an exposed situation where plants can dry out easily.

Roof terrace design

The project as a whole had many of the typical hallmarks of a London build. “Restricted space, high budget. And with that comes the need for some ingenuity to get everything in."

Robert trained in architecture. “I’m relieved I didn’t go into it. I feel like creativity is often stifled by legislation and other things.” However, he does feel it comes through into his creative designs in a positive way. “In the general appreciation of how to organise a space and how to understand the psychology of the space and how people are going to use it and want to use it,” he explains. “One of the keys to spatial design is that you move around and you don’t notice that the space has been so considered and it doesn’t feel planned.”

Simple though the space is on the roof terrace, this philosophy is apparent. Placing the planters and bench part way along one side draws the eye and encourages visitors to move in that direction. On the opposite side, at the end of the terrace, another group of planters draws flow across the space. This way visitors are gently encouraged to circulate.

Find more inspiration on how to use our Corten steel planters and check out our range of troughs, cubes, cylinders and tapered pots.