MODERN DECKING MATERIALS:
BY CHRIS SHORT OF ALFRESCO FLOORS
Personally, I blame Tommy Walsh. or contract in Summer and Winter). traditional hardwood market will be
Just 20 years ago cold, damp Britain The kiln drying process also makes completely replaced by these treated
was still happily hard landscaping the timber much harder and more softwood alternatives.
with frost bitten stone pavers and resilient to wear. Thermo-treated algae covered concrete slabs. Then the timbers are perfect for decking (and All these timber options will weather
garden DIY shows hit our televisions, cladding) and will be guaranteed rot down to a silver-grey over the
and a national obsession with decking free for at least 20 years. A personal first few years (some faster than
began. For the domestic market, favourite is Thermo-Ash, which has a others) but if colour fade is an issue,
this meant most of Finland was cut beautiful grain structure and goes a or slip resistance is a significant
into poorly preserved planks and rich chocolate brown in the kiln. consideration, then you now have
delivered to every garden centre in
an increasing choice of composite
the UK, while for the commercial Pressure treated timbers (like materials on offer. Commercial
market, it signalled the start of an Kebony, Accoya and Lignia) are more imperatives have accelerated the
ever growing demand for the tropical expensive to manufacture and to development of composite decking
hardwoods (like Teak and Ipe) which buy, but can have lifespans of over 50 faster than any other product recently
could actually withstand the rigours years, even in the most inhospitable – with hollow core, foam core, solid
of our weather. Early players in parts of the country. This process uses core, ‘double extrusion’ and even
the game, like The Outdoor Deck air-tight chambers to force a complex fire-rated options all competing for
Company, started importing much concoction of preservatives into every attention. As ever, it’s still largely a
more sophisticated treated softwoods cell of the softwood timbers, effectively matter of ‘you get the quality you pay
from the USA (where the industry was replacing the original organic content for’, but the manufacturing techniques
far better developed) but it’s only been with a dense and dimensionally stable are changing so rapidly in composites
in the last few years that affordable, new core. As with thermo-treatment, that its always best to chat with an
sustainable ‘technical timbers’ and the process creates timbers which are expert before you commit to one.
their composite alternatives have even more akin to tropical hardwoods started to make a major difference in their resistance to abrasion, and In summary, you can now assume that
to the economics and longevity of Lignia (the newest product in this many of the new ‘technical timbers’
UK decks. sector) can even be fire-rated as part will actually out-perform composites
of the treatment. in terms of thermal movement
If you’re exterior landscaping right
and durability, but composites will
now, and your requirement is for Thirdly, there is of course still a currently win out when you measure
real wood, you currently have three market for traditional hardwoods slip resistance and colour longevity.
categories of material to choose from... - though progress towards making The best news is that our industry is
these timbers sustainable over the now equipped with all sorts of viable
Thermo-treated timber is kiln cooked last decade has inevitably reduced and more affordable alternatives
softwood - a process which removes the choice and increased the price to traditional hardwood, so it looks
all the sugars (nothing for algae to significantly. It seems likely that as like our obsession with decking can
feed on) and most of the moisture the ‘technical timbers’ become ever continue, whatever the climate ahead.
(nothing to make the boards expand more sophisticated and affordable the
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Landscape & Urban Design Issue 36 2019