A shake fabricating process for producing roofing shakes from a lumber drop block having a natural grain and having an upper surface and an opposed lower surface is provided. In accordance with the process, the drop block is scanned for unacceptable grain structure. The drop block is cut across said natural grain into blanks having a length generally equivalent to the length of a roofing shake and including a first end section and a second end section. The blank is cut on a diagonal plane relative to the first and second end sections, the plane extending from the first end to said second end so as to divide the board into a pair of shakes, each shake having a first and second end portion and defining a decreasing thickness from the first end portion to the second end portion. The shakes are placed in a pressure treating chamber for treatment with a chemical preservative.