Siberian Larch FAQ - House Land Holz

Frequently asked questions

Every day we work with Siberian larch timber here at House Land Holz, so we wanted to share some useful tips and resources about each species. This FAQ goes into almost everything you need to know about Siberian larch timber.

Siberian larch is one of our favourite timber species and it is a popular choice for external projects. Make sure you check out our range of Siberian larch cladding, decking, battens or sawn timber and discover how you can use this timber to create a truly expectational exterior to your building or garden project.

Siberian Larch is a softwood timber species, the botanical name is Larix sibirica. Siberian Larch is also known as Russian Larch. Siberian Larch is very slow-growing and high-density wood which makes it one of the hardest softwoods on the market. Its 50% harder than Pine and this is one of the reasons it is so desired. Such high timber density makes it very durable and perfect for exterior projects. The shapes and patterns of the growth rings are very aesthetically pleasing and give each cladding panel real character. The lifespan of Siberian Larch is 50-100 years.

The timber is used for a wide range of joinery application such as cladding, decking, fencing and garden shed, office or furniture manufacture. The Siberian larch tree is a medium-sized deciduous, coniferous tree ranging in size from 20m to 40m tall with a diameter of 1m or slightly more. In favourable situations, a long, clean, cylindrical bole for two-thirds of its length can be achieved.

Due to the high percentage of heartwood (75-90%) and the minimal proportion of sapwood, Siberian Larch is an extremely dense timber, which is classified by BS EN 350-2 as approximately 630 – 650kg m³ with a moisture content of 18%.

The colour of Siberian Larch ranges from brown (Golden brown), Light brown, Reddish brown (Pale).

The best quality and durable Siberian larch grow in the colder regions of Russia (Siberia), hence the name Siberian Larch. Siberian larch is a softwood that grows in extreme weather conditions. These conditions give rise to a slow and regular growth, which make it more sustainable and more resistant, with a regular quality and less big knots compared to the European Larch wood.

Siberian Larch can be stained, it is important to make sure that the Siberian Larch is well kiln dried 18% moisture content and below. This is best done in a factory controlled environment a number of the timber cladding and decking producers supply factory stained Siberian larch.

Siberian Larch does not require treatment against biological attack mould and fungi that is for most applications when used above ground use class 3 for decking and cladding situations. However, we always recommend a treatment with primer and top coat to all sides of board.

If it is used for direct ground e.g posts and poles it needs to be treated. Siberian larch does not take pressure preservative treatments very well due to the tight structure and the high resin content. You will need to fire retardant treat Siberian larch if you need to improve the fire resistance or to improve the fire performance of the timber cladding e.g to Euro Class B, or Euro C EN 13501-1 or Class 1 or Class O in BS476 Part 6 and 7. Unfortunately we do not offer fire retardant treatment.

Siberian larch unpainted or stained will go silver as part of the weathering process. The weathering process of Siberian larch as any timber is a combination of various processes weathering includes weather elements rain wind, temperature, sunlight and mould on the wood surface. Siberian larch will go silver quicker when exposed to the exterior elements of rain, sunlight etc.

Siberian larch will weather into a silvery grey when exposed the elements, the weathering process occurs at different rates depending on the exposure elements and the intensity on the external elements. Siberian larch that is unexposed will turn silvery grey quicker to partly covered or covered Siberian larch there is not a fixed rate of weathering. The timber will turn dark brown before turning into silvery grey, in instances that the cladding has developed water stains or watermarks these do not become very visual as the weathering process evens out the colours. The colour difference is very distinctive in the early stages of weathering.

Siberian larch like most timber when used for cladding applications in thickness of 18mm and above in standard cladding configurations this is generally classified as Euro Class D and is a self-declaration for CE Marking for timber cladding BS EN 14915:2006 Solid wood panelling and cladding.

Siberian Larch is moderately durable it is important to make note of the origin of Siberian larch is has to be slower grown and heartwood. The Siberian larch when used for cladding and decking applications and well detailed should last more than 25 years.

Siberian larch needs to be installed with annular ring shank stainless steel nails or stainless steel screws. For most Siberian larch cladding with a thickness of 15mm to 25mm use nails that 50mm long.

Siberian larch can be cleaned by jet washing in areas with no staining or painting, stains in Siberian larch can be removed by using a wood reviver. For painted or stained or oiled Siberian larch – For factory finished Siberian larch touch up all exposed ends and splits or checks as they develop and use a soft, lint-free cloth or a large sponge and a neutral pH soap to remove any pollutants and scrap off any resin as part of the annual maintenance.

Siberian Larch is good for decking as it is naturally durable, dense and does not need any preservative treatment, it can be oiled and stained.

Siberian larch is used in a number of projects as is readily available, affordable, durable, no toxic, beautiful and can be enhanced with a number of techniques such as shou sugi ban, charring, burning, painting, oiling staining. It can be used for various joinery applications decking, cladding, garden furniture, windows and doors.

Siberian Larch is available in a wide range of standards for sawn Timber this is supplied based on the GOST grading rules U/S (I-III) Unsorted, S/F Sawfalling (I-IV) or Vth Fourths etc.

Siberian Larch is graded as follows for cladding 2 standards are used BS1186:3 1990 Part 4 for knot size and BS8605:2014 External Timber Cladding Part 1 – Method of Specifying.

BS1186:3 1990 (Timber for and workmanship in joinery) is the current British Standard relating to cladding. The definitions of quality largely relate to visual quality and the size and frequency of knots -classes are defined:


Grade A+ 

This is virtually a clear grade timber, providing a clean, consistent, almost knot-free look combined with excellent durability.

• Graded to BS1186-3 Part 4 Class 1; each board is practically centre pith free, one face will be sap free;
• Further hand-selection of clearest grade boards which meet stringent criteria; tight live knots with a maximum 20mm diameter and a maximum of two knots per metre on average over the total length of boards;
• As Siberian Larch is imported to the UK in board form, to avoid unsightly surface finishes such as circular-saw marks, paint / grease marks and compression marks from steel securing bands;
• Kiln-dried to moisture content of approximately 16-18% (+/- 2%);
• End checks permitted not longer than 1.5 times width of board;
• Best available grades in Europe and guarantee that your order will not contain any commonly available, lower quality grades such B or BC;


Grade A/B

• Graded to BS1186-3 Part 4 Class 2; each board is practically centre free, one face will be sap free, tight live knots have a maximum 35mm diameter and a maximum of two knots per metre on average over the total length of the boards;
• Kiln-dried to moisture content of approximately 16-18% (+/- 2%);
• End checks permitted not longer than 1.5 times width of board;
• The best available grades in Europe and guarantee that your order will not contain any commonly available, lower quality grades such B or BC ;

30 – 60 years. Due to natural resin and extracts in the wood, Siberian Larch is extremely hard wearing. This makes it one of the toughest and most durable softwoods in the world. For these reasons the timber makes excellent decking for both residential and commercial projects.

Our Siberian larch is a perfect choice for those designing on a budget but wanting a superior quality decking. Siberian Larch is naturally durable with a life expectancy of 30 to 60 years.

Siberian Larch is famous for its longevity and high quality. Durability under any weather conditions makes the wood suitable for exterior structures. It is strong, dense and resinous. Unlike most of the other species, Siberian larch does not require additional processing, which makes construction and production easier. Moreover, it does not rot in water, but hardens, and therefore is often used for the construction of underwater structures.

If left for around two years without any treatment, the wood will attain a natural grey ‘weathered’ look which, depending on your vision, is no bad thing. Monochromatic designs can add a touch of distinguished class!

Timber tends to warp or bend because of changes in moisture levels within the wood. As the moisture increases when exposed to the elements, the wood contracts or expands causing warping. The timber in Siberian Larch is so much denser, it offers much more natural protection by making it more difficult for moisture to penetrate the wood than with other types. Just as an example, untreated Siberian Larch has a wood density of 41lbs/ft3, but treated pine still only offers 35llbs/ft3 so your Siberian Larch offers more natural resistance to the elements around it.

A dry larch board at 145mm can change width by up to 5mm during the year. The wider the board the more it shrinks. Smaller baords will (for example) 70mm can change width by up to 2-3mm.

We would advise using only top quality stainless steel fixings to avoid corrosion and staining to the wood. Fixings can often be an afterthought, but with qualities that are present in Siberian larch, it’s important that everything from the fixings to the overall design reflect a sense of quality.

As with fixing to other timber species, using ring shank nails is our preferred option as it provides extra grip and support. The length of the nail should also be around 2 and 2.5 times the thickness of the board. This ensures for a good fix between the cladding and the batten.

Due to Siberian larch’s natural properties, it can be split on nailing so drilling holes is recommended before you fix the timber to the wall.