Profile: Sumsion Construction LC offers asphalt paving and maintenance services. We also specialize in seal coating, crack filling, patching and stripping. Asphalt overlay is the application of a new layer of asphalt to an existing layer of asphalt. An overlay adds the structural capacity of the existing surface. It also adds to the smoothness of the surface. Asphalt overlays are typically 1 or 2 inches. Seal coat provides a protective barrier for the surface of the asphalt. It stops water from petreating the surface, protect from ultraviolet rays and resists gas, oil & salts. Seal coat is a mixture of oil, water and slate. Crack seal is made of rubberized asphalt which expands and contracts with crack.