Oakleigh is a T-shaped Greek revival mansion featuring unique architectural features including a distinct cantilevered front staircase, grand double parlors and classic six-over-six windows and galleries accessed through jib windows. Roper was his own architect and builder. Using slave and free labor, the house is composed of bricks made from clay dug on the grounds and timber harvested from the property. Tool marks can be seen on the siding, doors and window frames.