Should I Powder Coat My Steel Planters?

The Landscape Architects Choice

The landscape architect of today can specify steel planters in a wide choice of surface finishes to blend in with – or provide a striking contrast to – the natural or built environment they contain or are surrounded by.

Unfinished, galvanised and weathering (CorTen) steel all offer a rugged industrialised look, but with a wide selection of colours available, powder-coated steel is the most aesthetically versatile option.

As one of the UK’s leading designers and manufacturers of roof garden and terrace systems, Raaft offers powder coating to match any standard RAL colour code at no extra cost. This allows architects to create a unified look for all architectural metalwork used in a project including balustrades, window frames, soffits, benches and street furniture.

The vast selection of colours also means that planters can be finished in muted, natural colours that act as an unobtrusive backdrop to spectacular planting displays and in fact, the most frequently specified colours are greys – RAL 7016 and RAL 7021.

But the RAL system’s wide colour palette also gives scope to be adventurous. Bold use of strong and often contrasting colours can inject energy and fun into an outdoor space.

The Pros and Cons of Powder Coating Steel Planters

Powder coating also gives a smooth, sleek finish that is more attractive and more durable than ‘wet’ paint finishes. At Raaft, once the planters have been fabricated and cleaned they are given a coating of cold-applied zinc-rich primer. This acts as a second line of defence against damage and corrosion while helping the powder coating to adhere soundly to the metal. Using a spray gun, the powder coating is then applied to the primed steel in a process that ensures the steel is coated evenly. Placed in a large oven, the powder melts and is transformed into a hard, smooth, enamel-like surface that is fully cured as soon as it is cool again.

So with so many benefits in its favour, are there any reasons why powder coating might not be the best finish? There aren’t many, but it’s good to be aware of them.

While powder coating is an extremely durable and weather-resistant surface, it can be damaged by sharp objects. A deep scuff or a scratch on an otherwise pristine, sleek surface can look unsightly and unlike ‘wet’ paints, powder coating cannot be repaired in situ. If the powder coating layer is penetrated as far as the raw steel, water may get behind the powder coating and cause it to flake away. For this reason, powder-coated planters may not be such a good idea in locations where there is a higher risk of accidental damage or vandalism.

Larger bespoke planters can also present a challenge for powder coating, as few powder-coaters have baking ovens large enough to take these as a single fabrication. Specifying powder coating for a large planter may therefore incur significantly higher costs, or require the planter to be fabricated and coated in smaller sections.

Powder coating is however an extremely popular, attractive and durable finish for outdoor landscaping and when specified appropriately will give many years of low-maintenance service.

It always pays to get expert advice before embarking on a first-time or ambitious project, however, which is why we would recommend you get in touch with the technical team at Raaft (call +44 (0)20 3146 7879 or email [email protected]). Friendly and knowledgeable, they will happily answer any questions you have on metal finishes, planters and roof terrace systems.