Aacer Flooring’s Unfinished Engineered flooring is available in three species, three thicknesses (1/2, 5/8, and 3/4 inch), and three widths (3 1/4, 5, and 7 inches). Northern red oak has a tight grain and a neutral color that allows for a variety of applied stains; northern white oak is straight-grained and ideal for custom staining; and northern hard maple features a denser grain.