This type of larch is being harvested in Czech Republic only in the region of Jeseník foothills and part of Silesia.
yellow–white to red–white sapwood, core–wood red–brown to dark red–brown, darkens. During stronger heating from the sun resin can seep through. Czech-Silesian larch has a higher amount of larger knots than Siberian larch.
Grade: A/B Siberian/Czech-Silesian larch
– yellow–white to red–white sapwood, core–wood red–brown to dark red–brown, darkens.
tangentially cut wood is used for facade profiles.
Additional information: Siberian/Czech-Silesian larch contains higher amount of resin which can seep through during stronger heating from the sun. Thanks to the higher contents of oily substances in the wood, larch can endure the outside climate even without surface treatment for a very long time. Sun, wind and rain will in time alter the colour of the larch wood, which will obtain the typical silver–grey patina. Larch facade boards are supplied according to ČSN EN 14519.
- Healthy wood with small amount of sapwood is used. differences in colour and graining are natural properties of wood and therefore have to be tolerated.
- Artificially dried wood meaning the moisture of wood is approx. 16–20% depending on the profile type.
- Profiles are planed with dimensional accuracy, deficiencies in the planing of tongue and groove may be individually included and also broken–out knots at the edges, where installation and functionality of the facade elements is guaranteed.
- Very occasionally small loose knots may be contained (max. diameter 15mm). Black and black–rimmed knots are allowed. split knots are allowed on the grading side as this is a natural property of larch wood.
- Splits on grading side (not running along the width of the board) may be contained up to a third of the total length of the board. End–splits are allowed up to the width of the board. Some of the typical properties are propensity to longitudinal splits and sap seeping, occuring during and after installation. For the removal of sap using OSMO sap removal is recommended. To avoid rust streaks, we recommend to use fastening and connecting materials from stainless steel. Due to the tendency of larch to cleave, all the connecting spots should be pre–drilled (especially at the edges and end of the boards)
- Resin pockets and core barrels are allowed in a reasonable quantity.
- Rotary growth is allowed if installation is possible.