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A naturally durable decking product which is ideal for high traffic areas.

Siberian Larch (SILA) decking is a naturally durable and aesthetically pleasing product which is particularly popular for projects which require both timber cladding and decking, as using SILA can create a consistent look throughout the exterior of the project.


Russwood’s SILA decking boards come in a warm range of colours, from light reddish brown through to golden browns.  The grain of the wood is straight and the annual rings are quite pronounced, showing a stunning variation in colour shades. This product meets customer demand for natural looking decks, as it boasts a high frequency of tight, live knots, enabling the deck to easily blend in to garden and park environments.

When weathered the colour changes to a muted shade of grey.  If used in a project alongside SILA cladding, the weathering of both products at the same rate will ensure consistency of the overall look over time. 

Grades and specification

At Russwood we sort and re-grade every SILA board that we produce, in order to ensure that our stringent in-house grading criteria are met. SILA decking is a selected grade, which meets the following criteria;

Specification for Siberian Larch Russwood SILA Decking

  • Graded to BS1186-3 Part 4 Class 2/3; each board is practically centre free, one face will be sap free, knots have a maximum 35mm diameter and resin pockets are restricted to a maximum of one per 2.5m length
  • Kiln-dried to moisture content of approximately 16-18% (+/- 2%)
  • Lengths up to 6.0m
  • Durability class 3 (BS EN 350-2 classification)
  • High density of approximately 628 Kg/m3 at a moisture content of 16-18% (BS EN 350-2 classification)


One of the primary benefits of SILA as a decking material is that it is one of the toughest and most durable softwoods; unlike most commonly available decking timbers, it is naturally durable, being rated as Class 3 according to BS EN 350-2. This means that it does not require any chemical treatment and, as such, has enviable environmental credentials.This natural durability is the result of resin and extracts in the wood, combined with a high density, which ensures that the wood is resistant to rot, decay and insect damage. This is of key importance when considering a decking material, as a hardwearing timber is required in order to ensure the long-term safety of the deck, regardless of its environment and level of footfall.


Russwood’s SILA is kiln-dried to approximately 16–18% (+/- 2%), the optimal moisture content for external decking. The benefit of kiln drying SILA, as opposed to air drying it, is that the timber dries uniformly and therefore achieves optimum stability. Once the SILA is kiln-dried, this enables machining of the product to achieve a superior finish. It is then ensured, through the use of stringent quality control processes, that the optimal moisture level is retained until delivery to site. The decking can then be installed immediately upon delivery.


Due to its high percentage of heartwood (75-90%) and a minimum of sapwood (we guarantee that at least one face will be sap free) SILA is an extremely dense timber, classified by BS EN 350-2 as approximately 628 Kg/m3 at a moisture content of 18%. As such, it is not easily damaged and therefore is ideal for high traffic areas such as bridges, hotels, retail outlets and other commercial properties.

Treatment suitability

Due to the natural durability and beauty of SILA decking, it is generally left untreated to weather to a beautifully consistent shade of silver/grey.

Slip-resistant finish

GripDeck® is a highly effective slip-resistant solution which can be applied in-house to our SILA decking, two strips per decking board will provide excellent slip resistance in both wet and dry conditions. The specially bonded aggregate inserts provide an attractive and long-lasting solution to slippery decking, being rated as “extremely low potential for slip” (BS7976:2002 Part-1 3 using the Stanley Pendulum Test). GripDeck® is particularly desirable for bridges, stairs, ramps, forest walkways and commercial environments such as cafes, pub gardens, shopping centres and parks.


The way a decking board is fixed and detailed can have a major effect on it’s lifespan. We have teamed up with Austrian fixings specialists, Sihga, to provide a system that makes decking look better and last longer. These systems can be written into the NBS Q55 specification. For more information, click here.


Russwood’s SILA is FSC®-certified, meaning that it is sourced from well-managed forests.


The standard SILA decking profile is a 120mm x 28mm smooth profile, which allows the creation of a contemporary look to suit the minimalist style of many modern domestic and commercial buildings.


SILA decking is supplied in various lengths from 1.8 – 6m. Please note that decking is supplied as a linear meterage based on random stock lengths at time of picking order. Other sizes may be available on request.


SILA is one of our mid-range decking products, with prices starting at £41m2 excluding VAT for the standard profile.


  • Particularly suited to high traffic areas
  • Excellent natural durability; no treatment required
  • Can be fitted with GripDeck® slip-resistant strips
  • Sustainable
Coast2Coast Architects
Russwood has an outstanding record of customer care – excellent attention to detail and quality of advice coupled with solving any problems that arise quickly, efficiently and to the customer’s satisfaction.

Greig Munro, Coast2Coast Architects