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Larch is a conifer tree (softwood) of the genus Larix that grows across the northern hemisphere. There are about 10 species included in the genus, but the most commonly used for cladding are: Siberian Larch (Larix sibirica) and European Larch ( Larix decidua).

Siberian Larch is considered a naturally durable timber for use in cladding applications (according to BS EN 350-2). It is also cheaper than Western Red Cedar, making it a fantastic option for resilient and sustainable natural cladding projects.

Fun fact: Even though Larches are conifer trees, they lose their needles in the autumn, making them deciduous softwoods!

 

Here are the main differences between commercially available larch species for cladding:

Siberian Larch (Larix sibirica)

slightly to moderately durable

straw colour with brown knots

denser than European/British Larch

available in two grades: Unsorted (fewer knots) or Sawn fallen (more knots),

longer lengths

 

European Larch / British Larch ( Larix decidua)

consistent pale pink colour with dark knots

slightly to moderately durable

cheaper

Ecochoice delivers Larch cladding directly to your project’s site in a range of profiles, including shiplap, TGV, tongue-and-groove and many others

Trade Name Siberian larch
Species Larix siberica
Intended use External cladding
Other uses Decking, joinery, structural timbers
Appearance The wood is a golden yellow colour with a strong grain pattern, similar to pine. Depending on the grade, the boards may include some, or many, dark black knots.
Weathering As the boards weather the colour will change to a silver-grey. Larch is quite consistent although weathering will depend on shade, ventilation, pollution and moisture.
Profiles Shiplap, halflap and splayed profiles. Not recommended with tongue and groove profiles (VTG) due to movement.
Dimensions 20×70, 20×95, 20x145mm
Lengths Random 1.8 – 4.5mt +
Moisture content Approx 16 – 18%
Natural durability (EN350-2) Durable Class 3 (Slightly durable, Moderately durable)
Insect attack Resistant
Desired service life:(BS8417) Occasionally wet 30 yrs
Frequently wet 15 yrs
Treatability class Resistant
Movement class Medium
Resistance to impact High
Resistance to fixing Medium
Mean density 570 – 650 kg/M3 when dry
When to fix Ideally Autumn / winter months.
Grading Grade B (Known in the trade as 4ths or Sawfalling). Too knotty to conform to any standard.
Grade A (Confusingly known in the trade as Unsorted) BS1186-3 1990 Class 2. EN942:2007. J30. CE grade A. Clean with a few sound knots up to 30mm.
Working properties Good workability. Takes fixings satisfactorily, although we always recommend stainless steel fixings.
Extractives Siberian larch contains resin rather than oil or tannin. The resin is fixed by kilning and does not tend to bleed.
Emission of formaldehyde (EN14915) E1 (Not significant)
Reaction to fire (EN14915) Euroclass F (Untested). D-s2, d0
Fire treatment Possible by impregnation after kilning
CE compliant Yes

We took care compiling this info, however Ecochoice Ltd will not be held responsible for any consequences arising from any errors or omissions on this website nor for any damages resulting from the use of the information.

Larch related insights

Case study: Siberian Larch cladding

EcoChoice recently supplied timber cladding for a project on the edge of the Peak District National Park. The building, which had been completely renovated, was clad in Siberian larch and the finished result looked fantastic.

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