 This study produced fiber boards from sheds extracted through continuous mechanical extraction of oleaginous flax straw and studied their properties through thermopressing and water resistance testing. The influence of two pretreatments and lignin addition on the boards' properties was investigated, resulting in cohesive hard boards that complied with the requirements for Type P1 boards for general use in dry conditions. This article was offered by Philippe Yvonne, Benjamin Bart-Hodmellat, Marie Grégoix and others.