Solid wood flooring is made of boards entirely in the same wood, with or without tongue and groove, according to dimensions. Pre-finished floorboards are the evolution of wood flooring: in this case Itlas greatly improves dimensional stability by providing a two or three layer board in which the top layer of solid wood is stabilised by a layer of birch plywood for Legni del Doge. For extra large boards, such as Tavole del Piave and Assi del Cansiglio, a third layer of solid fir wood is added. The system is a patented industrial invention.