The invention pertains to a method of manufacturing a fire proof board from strands of wood, the method comprising the following steps in the given order: (a) providing strands of wood having a humidity between 5% and 25%, preferably between 5% and 20%, even more preferably between 8% and 20%, (b) immersing the strands of wood in a watery solution of a flame retardant chemical composition, (c) separating the strands of wood from each other, (d) at least in part drying the strands of wood thereby providing dry impregnated strands of wood, (e) applying an adhesive to the strands of wood, and (f) forming a board of a predetermined shape from the strands. The invention furthermore pertains to a board formed by a plurality of strands of wood that are compressed and bonded together with an adhesive, wherein the board further comprises a flame retardant chemical composition, said composition comprising a phosphate compound.