The flexible base overlay has been used as an intermediate layer of a new structure, placed directly on top of an old structure. The primary purpose, in addition to increasing structure, has been to resist the propagation of reflective cracks from the old structure. The existing structure still offers good/uniform support. A suitable surface designed for the expected traffic loading must also be planned. As such, this type of rehabilitation can increase the overall highway profile considerably. The material proposed for the new flexible base should be evaluated for moisture susceptibility and durability; trapping moisture in the flexible base overlay between the old highway surface and the new surface must be avoided.