Published: May, 2018
Both can be used for stunning effect but how to choose. Architects in search of something more exciting than concrete pin kerbs for dividing different surfaces have been turning to steel and aluminum edging for years. Both metals allow a far more bespoke and creative approach, as well as coming in a range of standard products, but which one works best?
Actually, it’s a pretty straightforward choice. It all comes down to the nature of the adjoining landscape surfaces and how much foot or vehicle traffic they’ll have to support. Kinley supplies both aluminum and steel products in its ExcelEdge range.
When there’s a really big landscaping project, with heavy traffic, then steel edging is the best bet. It’s also the right choice if one surface is higher than the other as steel edging’s greater strength and durability holds an abutment firmly in place.
In most other circumstances, ExcelEdge aluminium edging will win out. It’s great to work with - flexible enough for curves and gradients but strong enough to earn its keep dividing flower beds and gravel paths and create all manner of lawn and landscape styles.
Because curves and gradients can be easily formed with these types of edging, the time-consuming base preparation associated with traditional kerbing is totally eliminated. And there’s no possibility of breakages, unlike when concrete curbs get mechanically manoeuvred into place.
That’s the headlines – let’s look now at the two edgings in a bit more detail and see which is best for you.
Aluminium has become the most popular choice for landscape architects for a host of reasons. Its flexibility makes it ideal for curves and gradients, even in the most complex designs, and the discreet edge detail creates pleasing aesthetics.
Another big plus is lightness. One-fifth the weight of steel, it’s so much easier to move around and manoeuvre on site, making installation far less hassle than with steel. Being lighter means cheaper site transportation costs too.
It’s also strong. The latest AluExcel edging that Kinley supplies is actually the strongest and most robust on the market – 30% stronger than any equivalent. Redeveloped in 2012 to optimise the profile strength to the amount of aluminium being used, it’s now at least 20% stronger than previous offerings.
That’s because AluExcel aluminium edging restraint is made from grade 6005A alloy and is tempered and hardened to T6 designation.
As well as being strong, this grade of alloy has excellent corrosion resistance and a good surface finish. That also equates to minimum maintenance, another big plus for any gardener, plus total suitability for the weathering challenges of seaside locations.
Why does it resist corrosion so well? It’s all down to oxidation. Aluminium is a very active metal and oxidizes, or “rusts”, speedily into A1203 to form a surface layer of aluminium oxide, and this seals the core aluminium from any further reaction. As it oxidizes and its oxidized layer increases, its protection increases – what’s known as self-passivation. The thicker the oxide, the slower the process until it all but stops. It’s quite different to oxidation on steel, where rust puffs up and flakes off, constantly exposing new metal to corrosion.
Environmentally, aluminium edging scores very well. The AluExcel that Kinley stocks is made from almost 100% recycled aluminium and is 100% recyclable. For an even more environmentally friendly option AluExcel's dry fix installation process means there's no need for concrete.
So, whether it's asphalt, resin bonded or loose gravel, blocks, bricks, paving slabs or kerb edging, AluExcel works well with them all. Plus, it can be powder-coated to any RAL colour and it's available from Kinley in the widest range of profile heights in the world, from 18mm-150mm, making it the most versatile landscape edging system in the trade.
When renowned architect Andres Duany of Duany Plater-Zyberk (DPZ) was designing a new sustainable community in Aberdeenshire, Chapelton of Elsick, the landscape architect Laura Scott-Simmons of Benton Scott-Simmons selected ExcelEdge AluExcel to create the development’s public footpaths. Concrete pin kerbs wouldn’t allow her to build in the range of diverse geometries she was after. And as a 100% recyclable material, AluExcel fitted the sustainability brief perfectly. See case study….
We’ve already noted ExcelEdge range is perfect for defining where differing landscape surfaces meet. Architects and designers can build complex and pioneering outdoor environments – anything from roof spaces to parks – which ExcelEdge will bring to life.
Steel edging, however, is the perfect choice for demanding locations such as lawn edging in busy parks and public spaces, where they’ll have to withstand much harder wear.
The heavy-duty roll-topped steel angle edging Kinley supplies is suitable for blocks and pavers, asphalt, loose gravel, imprinted and plain concrete and resin-bound and loose gravel.
It offers strength and robustness, adaptability for straight or curved lines and fast, simple installation. With a range of grades, formats and finishes, there are bespoke steel edging options available for hard and soft landscapes, special finishes and raised edges. And it’s available from Kinley in in a range of finishes including mild steel, CorTen, stainless, galvanised and powder coated.
When installed, galvanised steel edgings should be cleaned thoroughly. If the galvanising is chipped or the steel is exposed in anyway, it should be coated with galvanised paint to avoid surface corrosion. Stainless steel edgings should require minimal maintenance, particularly in external applications.
A fine example of steel edging is at the International Bomber Command Memorial Centre in Lincolnshire. Kinley Verge Steel Edging has been used for gravel areas encircling each of the CorTen ‘wall of names’ which commemorate thousands of Second World casualties, as well as in the landscaped garden areas. All to stunning effect, as we hope you’ll agree.
View the Project
International Bomber Command Memorial, Lincolnshire
Kinley were honoured to be involved in the landscape scheme commemorating the 55,573 men from International Bomber Command who made the ultimate sacrifice whilst serving in 1 and 5 groups, both headquartered in Lincolnshire.