Siberian Larch Heavy Charred and Oiled Tongue and Groove Shadow Gap 21x145mm. The technique of scorching and burning cladding has been used for centuries by the Japanese. The carbon layer not only enhances the durability of the timber, but also creates a beautiful black aesthetic. The production process includes machining the larch cladding to the tongue and groove shadow gap profile, Heavy burning on 2 edges and one wide face, followed by application of 2 coats of oil help protect the charr Supplied in 5m2 (10 pieces) in 4.0mtr lengths. This can be used to clad horizontally and vertically. All prices include VAT.