The surface is close-grained and its appearance very beautiful and uniform. Spruce plank in 3-layer construction with small bevel on long side and approx. 4 mm top layer, with approx. 4 mm backing in the same wood and middle layer conifer. Tongue and groove on all sides for easy installation. Isolated fillings and small pitch pockets are possible. Healthy knots (max. 35 mm diameter) and splay knots (max. 20 x 60 mm), are permitted. Knotholes of up to 20 mm diameter are closed with appropriate wood putty. Sealed cracks up to max. 1/3 of plank length are possible.