Oak plank in 3-layer construction with large bevel on all sides 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. End cracks, stress cracks and knotholes up to 30 mm are permitted and sealed with appropriate putty. Variations in color and sapwod are characteristic. Small open cracks and unsealed spots of a few millimetres are permitted.