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Siberian Larch Decking Unsorted (I-III) 27 x 140mm

Price From: (exc VAT) £13.35 (inc VAT) £16.02
(exc VAT) (inc VAT)
Price per linear metre £4.45 £5.34
Price per square metre £30.69 £36.83

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Price From: (exc VAT) £13.35 (inc VAT) £16.02


The natural properties of Siberian Larch make it an excellent material for timber decking. Aside from its aesthetically pleasing golden brown colour, it can also boast to be one of the world’s most durable softwoods. Add to that its impressive dimensional stability and the fact that Siberian Larch has the highest density of any commercially available softwood species and you have a natural decking product that will outperform anything else on the market at its price point.

At a glance

  • Naturally durable
  • Unsorted (I-III) Grade
  • Aesthetically pleasing golden brown colour
  • High level of density and hardness
  • Dimensionally stable

About Silva's Siberian Larch Decking

Silva’s FSC certified kiln dried Siberian Larch decking is well manufactured. Boards are of a consistently high quality – exceeding the official industry recognised GOST 26002–83 grading standards.

Deck boards are planed smooth with a radius edge so the finished deck surface will be both comfortable underfoot and pleasing to the eye.

The timber used to manufacture Silva’s Siberian Larch decking is cut from sustainable old growth logs harvested in the Irkutsk region of Siberia.

Wood fibre from this harsh climate (long cold winters) is much sought after for its natural growth characteristics – exceptionally slow growing therefore dense with tight grain and relatively few well interspersed small sound knots.


About Silva’s Siberian Larch Decking

Silva’s Siberian Larch decking is produced from a consistent and reliable raw material that is kiln dried at source to a moisture content of 16 – 18% (+/-2%). Among its many benefits the kiln drying process enables the boards to dry uniformly to achieve optimal stability, have a finish applied immediately and to be installed without the need for acclimatisation on site.

Siberian Larch heartwood has a colour palette consisting of aesthetically pleasing warm golden brown, light brown and pale red brown tones.

The raw material is manufactured by one of the leading primary producers of Siberian Larch in the Irkutsk region of Siberia. With immediate access to a plentiful supply of old growth logs from this vast forest area, our supplier is able to provide us with Siberian Larch of an exceptional quality that exceeds the official GOST (26002-83) grading standards.

The wood fibre from this region is characteristically dense with exceptionally tight grain, a consequence of the slow growth rate of the trees in this harsh climate.

Siberian Larch – the ‘Tree of Eternity’

Siberian Larch is a sustainable, old-growth timber that has been used in construction for centuries. Today it is used extensively throughout Europe, primarily for external applications such as cladding and decking, and for other uses including flooring, bridges and even Olympic velodrome tracks.

Its remarkable qualities and unique performance characteristics have led to it being referred to as the 'Tree of Eternity'.

Decay Resistance

Natural resins and extractives in Siberian Larch provide a high level of resistance against decay and rot. The primary extractive in Siberian Larch is arabinogalactan which is toxic to fungi. Siberian Larch is rated as Durability Class 3 according to BS EN 350-2 and therefore does not require pressure impregnated chemical preservatives (not to be confused with decorative / protective wood finishes).

Grain and Texture

Siberian Larch has straight grain with a fine uniform texture.


Silva’s Siberian Larch grows in an ‘extreme continental climate’ which is characterised by long cold winters and short hot summers. As a consequence trees grow more slowly and contain a high proportion of latewood. This is the part of the wood in a growth ring of a tree that is produced later in the growing season. The cells of latewood are smaller and have thicker cell walls than those produced earlier in the season. The resulting wood fibre is tight grained, dense ( 570 - 650 kg/m3 when dry) and hard. In fact Siberian Larch is the hardest of all commercially available softwood species. It has a Janka scale rating of 1100 lb/in2 (European Redwood is 480 lb/in2). This makes it more resistant to impact and abrasion than many other wood species and therefore well suited for use in public areas where wear and tear may be of concern.

Large content of heartwood

Siberian Larch trees are composed of 75-90% heartwood in their natural existence, which is denser, less permeable and more durable than sapwood. Heartwood provides maximum durability, consistent quality and a more uniform colour.

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Finishing & Protection

It is recommended that a finish is applied to all surfaces, including ends, before installation. The type of coating will be determined by the final finish and appearance desired.

Why Pre-finish?

  • Enhances the natural beauty of wood
  • Ensures a consistent finish
  • Applied in factory conditions
  • Long lasting protection against weathering
  • Simple maintenance routine
  • Reduces onsite labour costs

Sansin Enviro Stains

Easy to apply and maintain, Sansin Enviro-stains deliver outstanding performance. Sansin's range of wood protection products are available in 80 colour tones

What is weathering?

There is a risk involved when leaving wood exposed to the elements. During the weathering process wood can appear unsightly as the material can blacken due to moisture getting into the fibres and pulling out tannins and extractives. Finish protects the wood from moisture absorption and UV degradation.

What to Expect from Timber Products

When working with timber it should be expected that although ‘on-grade’, occasional boards may have minor imperfections that will require ‘working’ if you wish to eliminate. Examples include raised grain, small splits, minor handling marks, sticker marks etc – all of which can easily be remedied by trimming, gluing or sanding. In most cases imperfections can be removed with very little effort, and the small amount of off cuts generated as a result will be absorbed in the normal cutting and selection allowance.


Now you can buy decking pre-sanded on the surface to save the hassle of onsite preparation work

The secret to a perfect finish is to sand the surface prior to applying the coating. The more care taken with preparation, the more finish will penetrate the wood, providing an even, consistent and long-lasting finish. Studies have proven sanding can extend the life of a finish by up to 3 times compared to an unsanded surface.

Click here to find our more about the importance of sanding

For a pre-sanding quote for your project feel free to contact us


The main commercial 'appearance' grades of timber from Russia are available in five distinct quality divisions. These grades are assigned Roman Numerals going from I ('Firsts') - which denotes the best looking timber, down to V ('fifths') which denotes worst looking timber.

It is not possible to buy higher appearance grades from any Russian producer in all 'First' grade for example. Higher grade timber from Russia is nowadays sold as a mixed assortment.

The highest commercially available 'appearance' grade of Siberian Larch is known as 'Unsorted'. Although the name would suggest that the material has not been sorted the timber has been sorted into the highest three appearance qualities - I,II & III or 'firsts', 'seconds' and 'thirds' (or simply described as I-III). 'Unsorted' grade Siberian Larch therefore consists of a mix of grades I - III.

The difference between the 'Unsorted' and 'Sawfalling' grades is that the latter also includes IV ('fourth') grade in the mix, therefore 'Sawfalling' consists of a mix of grades I - IV. The actual percentage of each quality division in any one shipment or pack of both 'Unsorted' and 'Sawfalling' grades correlates with the natural recovery of the timber while sawing.

For full grading information click here


Independently Verified Environmental Credentials

Siberian Larch is one of the few old growth species that are being harvested from a sustainable forest. Larch species actually account for 38% of the timber in a forest area 2.7 billion acres in size. The natural growth rate of Siberian Larch is five times more than the rate at which it is being harvested, making it a sustainable renewable resource that is in plentiful supply.

Silva Timber takes great care in ensuring that the Siberian Larch we buy comes from a sustainable source – it is fully FSC certified.

This product carries Forest Stewardship Council (FSC) Accreditation

FSC is a world-wide, independent, non-profit, non-governmental organisation representing environmental and social groups and the timber and forestry industry. It aims to generate certification of forestry activity that incorporates clear guidelines and standards covering social, environmental and economic aspects of forest management.

Established in 1993 as a response to concerns over global deforestation, FSC is widely regarded as one of the most important initiatives of the last decade to promote responsible forest management worldwide

The FSC label provides a credible link between responsible production and consumption of forest products, enabling consumers and businesses to make purchasing decisions that benefit people and the environment as well as providing ongoing business value.


Chain of Custody (CoC)

The FSC Chain of Custody (CoC) certification system provides an audit trail from forest to final use. The rigour of the system is ensured by regular independent inspection at all stages in the supply chain.

FSC chain of custody (CoC) tracks FSC certified material through the production process - from the forest to the consumer, including all successive stages of processing, transformation, manufacturing and distribution.

Only FSC CoC certified operations are allowed to label products with the FSC trademarks. The FSC label thus provides the link between responsible production and consumption and thereby enables the consumer to make socially and environmentally responsible purchasing decisions.

Silva Timber Products meets the requirements for FSC Chain of Custody Standard FSC - STD - 40 - 004 (2004) within the BM TRADA Certification Limited Scheme for TRADA - Trak chain of custody certification

Certificate number:- TT-COC-002296

  • FSC
  • PEFC
  • Trada member
  • Responsible purchaser
  • Cedar Shake & Shingle Bureau
  • nbs plus
  • Secured by