Need help? Ask an expert

01540 673 648

My lightbox (0)
Add products to lightbox to review choices & request samples

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 many project types.

Appearance

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. In ideal conditions, this species weathers to a muted shade of silver / grey which is 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.

Grades and specification

At Russwood we sort and re-grade every Scottish Larch board that we produce, 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
  • Air-dried to moisture content of 16-18% (+/- 2%)
  • Lengths up to 4.8m
  • FSC-certified product sourced from sustainable forests in Scotland, certification no - FSC-C017490

NBS Specification

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

Durability

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 tannins in the wood which create a resistance to decay.

With correct detailing (i.e. no sapwood on exposed faces) and appropriate fixings, Scotlarch® cladding should have a lifespan potential of at least 30-50 years. 

The way a façade is fixed and detailed can have a major effect on it’s lifespan. Our range of fixings and systems are designed by Austrian Timber Engineers to make cladding look better and last longer. 

Stability

Russwood’s Scotlarch® is carefully air-dried to 16 – 18% (+/- 2%), the optimal moisture content for external larch cladding. The benefit of air drying this product, as opposed to kiln drying it, is that the timber is not subjected to the stresses of kiln drying, and therefore achieves optimum stability.

Once the Scotlarch® is air-dried, this enables machining of the product to achieve a superior finish. It is then ensured that the optimal moisture level is retained until delivery to site. The cladding can then be installed immediately upon delivery.

Density

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, supermarkets, visitor centres). 

Coating suitability

Scotlarch® is suitable for vacuum coating in SiOO:X, a breakthrough silicon technology, to provide a genuine silver lustre. In effect, SiOO:X creates a weathered appearance at an accelerated rate. Following application, all areas, regardless of protection and exposure, take on a consistent tone which provides a solution to differential weathering. For further information about SiOO:X click here.

Scotlarch® can also be coated in your choice of colour from Russwood’s Teknos paint 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 within this PDF or by contacting our technical sales team to discuss further.

Scotlarch® is also suitable for fire-retardant treatment.

Fixings

How timber is fixed is fundamental to it’s long term performance in terms of both appearance and durability. We offer a range of fixings and systems to make cladding look better and last longer. These systems can be written into the NBS H21 specification. For more information on our recommended fixings, click here.

Profiles

We can advise you on the most suitable species and profile for your project. Visit our profiles section to view some of our most popular profiles, or speak to us to discuss further options.

Sustainability

Most of our Scotlarch® originates 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.

Size

Scotlarch® is available in varying lengths of 1.8m up to 4.2m, sawn widths from 47mm to 150mm, and sawn thicknesses of 22, 30, 35 and 50mm. Please note that cladding is supplied as a linear meterage based on random stock lengths at time of picking order. Other sizes may be available on request. 

Price

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

Summary

  • Locally sourced product
  • Innate durability
  • Natural look
  • Weathers to a muted grey tone
  • Sustainable

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

Profiles

Please note that we have only listed the most popular profiles for each product but there may be others available. Please speak to us to discuss the best options for your project.

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