Abstract: A riser assembly and method for engaging the same to raise a manhole cover to be flush with an inclined paved surface after the application of an additional layer of paving material thereto. The riser assembly includes a first and second riser frame with a plurality of specially manufactured spacer blocks fixedly secured between them. The spacer blocks have progressively different height dimensions and sloped upper surfaces so as to create an angle between the first and second riser frames. The angle is complementary to the slope of the paved surface. The riser assembly includes an expansion device for adjusting the diameter of the second riser frame so that it frictionally engages the existing manhole frame. The fixed securement of the spacer blocks prevents relative movement between the first and second riser frames even when the diameter of the second riser frame is changed.