Solid wood elements with groove and/or tongue according to EN 13226 are solidwood strips of soft- or hardwood with a thickness ≥ 14 mm, which at one longitudinal side and at one width side are provided with a groove each and at the respectively opposite side with a planed tongue each. In Europe, solidwood elements are usually manufactured with thicknesses of 22 mm, but thicknesses of 15 mm, 16 mm, 19 mm, 20 mm und 23 mm are also common. The product is defined with a length more than 250 mm and a with above 40 mm. The edges of the elements may be bevelled; the bottom side may have one or several adhesive rebates. For elements without surface treatment, the top side must be smoothed. The type of wood is selected depending on the requirements of use in the structure and must be stated. The most common types of wood (hard- and softwoods) are listed in Appendix A of the standard EN 13226. Sorting is undertaken into the three appearance classes ⚪, △ and ◻. According to the national preface of EN 13226, in Austria the free sorting "exquisite" (for oak, ash and beech) is used for determination of the sortings. Depending on the manufacturer further free sortings (classes) are also possible, they have to correspond to the principles of Appendix B of the standard EN 13226. The fire behaviour of the parquet is classified according to the classification report of the manufacturer or according to EN 13501-1 (Cfl-s1, Dfl-s1, Efl – according to product details and end-use condition). The CE-certification of wood flooring and parquet has been compulsory according to EN 14342 since 01.03.2010.