Abstract: A core for a fire rated door includes an extruded fire resistant material, a filler material and a panel. The extruded fire resistant material has a first raised portion, a second raised portion and a lower portion that extends from a first end to a second end. The first raised portion has a first thickness and a first width that extends from the first side to the lower portion. The lower portion has a second thickness. The second raised portion has the first thickness and a second width that extends from the second side to the lower portion. The filler material is disposed above the lower portion of the extruded fire resistant material between the first raised portion and the second portion. The panel is attached to the first raised portion and the second raised portion of the extruded fire resistant material and covers the filler material.