Scotlarch® Cladding

A selected grade of Scottish Larch which is locally-sourced, sustainable and naturally durable.

Russwood’s Scottish Larch (Scotlarch®) is locally sourced timber which provides a durable, natural and cost-effective cladding solution.  As the construction sector becomes increasingly focused on combining energy efficiency and sustainability with the need to cut costs, Scotlarch® is the timber of choice for all project types.


Russwood only supply cladding using selected heartwood of Scotlarch®, with boards encompassing a warm mix of colours; from pale orange/brown through to reddish brown shades.

This species weathers very consistently to a striking shade of silver/grey, which is highly desirable in many cladding projects.

There are frequent knots in Scotlarch® boards, which demonstrate the natural origins of the product and give it a characterful look.


Due to its high percentage of heartwood and minimum of sapwood (all exposed faces will be sapwood free) Scotlarch® is a medium density timber, classified by BS EN 350-2 as approximately 556 Kg/m3 at a moisture content of 18%.  As such, it boasts excellent impact strength and therefore is ideal for highly exposed elevations, or applications where there is the likelihood of physical damage such as knocks or scrapes (e.g. schools, shopping centre, public walkways).


Scotlarch® is a naturally durable timber and, for external cladding purposes, is classed as “moderately durable” (class 3 according to BS EN 350-2).  This is due to the resin and extracts in the wood which create a high resistance to decay and rot.

With correct detailing (i.e. no sapwood on exposed faces) it contains minimal sapwood and thus can have a good lifespan potential of at least 30-50 years (realistically it can be expected to last twice as long as this). 

Grades and specification

At Russwood we sort and re-grade by hand every Scottish Larch board that we receive, in order to ensure that our in-house grading criteria are met.

Heartwood of Scottish Larch; Russwood Scotlarch®

• Graded to BS1186-3 Part 4 Class 2/3; under 20% of each order will contain Class 3 boards, which may contain sound, live knots with a maximum diameter of 50mm
• Sapwood free on all exposed faces
• Some resin pockets may be present
• Kiln-dried to moisture content of 16-18% (+/- 2%)
• Lengths of 1.8 – 4.8m (moulded profiles may contain a maximum of 5% below 1.8m)
• FSC-certified product sourced from sustainable forests in Scotland


Russwood’s Scotlarch® is kiln-dried to 16 – 18% (+/- 2%), the optimal moisture content for external cladding. The benefit of kiln drying this product, as opposed to air drying it, is that the timber dries uniformly and therefore achieves optimum stability. 

Once the Scotlarch® 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 cladding can then be installed immediately upon delivery.

Treatment suitability

Although Scotlarch® is generally used uncoated, in order to illustrate the natural beauty of the product when weathered, it is also suitable for vacuum coating with your choice of colour from Russwood’s Teknos range. We recommend using a sawn-faced profile when painting Scotlarch®, in order to minimise the visual effect of resin exudation - a natural occurrence which may affect some boards. More information on resin exudation can be found here or by contacting our technical sales team to discuss further.

Scotlarch® can also be fire-retardant treated, using either the NON COM® process, or using HR Prof as an on-site applicant. 


Most of our Scotlarch® originates from within 100 miles of our Highland sawmill.  In addition to the sustainability benefits this affords, Russwood’s Scotlarch® is FSC®-certified, meaning that it is sourced from well-managed forests.


Scotlarch® is available in standard lengths of 1.8m up to 4.8m, widths of 75, 100, 125 and 150mm, and thicknesses of 22, 30, 35 and 50mm.  Please note that these are standard sizes, but other sizes may be available on request.


Scotlarch® is our most cost-effective cladding species, with prices starting at £17 per m2 for sawn boards.

NBS Specification

For advice on completing the NBS H21 for Scotlarch® please get in touch with our technical team.


  • Locally sourced product
  • Innate durability
  • Natural look
  • Consistently weathers to a beautiful silver/grey
  • Sustainable

For a printable summary of the above information, click here to download our Scotlarch® Cladding Factsheet

What our customers say about Scotlarch® cladding

  • Matthew Bradshaw, BDP

    “It is important to us to source sustainable and affordable timber from within the UK.  At Bents Green School, Russwood provided us with friendly, detailed, and extremely helpful technical guidance, and in Scotlarch® a timber cladding which is attractive, flexible in design terms, and met our budget requirements.”

    Matthew Bradshaw, BDP
  • Jenny Humphreys, Simpson & Brown Architects

    “Russwood have provided us with high quality, Scottish timber on many occasions and we trust them implicitly to meet our needs – however unusual our request!”

    Jenny Humphreys, Simpson & Brown Architects
  • Colin Anderson, G D Lodge Architects

    “I have found working with Russwood to be an enjoyable and informative experience. They offered an unparalleled level of technical expertise and advice from the project’s early stages and provided a first class advisory service on site. We and, most importantly, the client are very satisfied with the quality of the finished building.”  

    Colin Anderson, G D Lodge Architects