Ash planks, in a 3-layer construction, with a small chamfer along the length and approx. 4 mm counter-move made from the same wood type, and a softwood middle layer. Tongue and groove on all sides for endless installation. The planks are mostly sound knots. There are no color contrasts present in the ash core. Tension cracks up to 30 cm as well as branch cracks and small knots are filled with suitable wood putty. Putty fillings up to 25 mm circumference are possible. Small open cracks and unsealed spots of a few millimetres are permitted.