- Every driveway must start out with a good solid foundation
- Should be properly excavated removing any unsuitable material such as sand, top-soil, clay, large stones, and other materials such as tree roots
- Once excavated a suitable sub-grade material (processed gravel), should be installed
- This work is usually done during site preparation leaving plenty of time for compaction and setting
- It is recommended that the sub-grade material be placed at a minimum of 6-12 inches depending on the existing conditions
- Generally the sub-grade is prepared leaving 2-4 inches for base and top coat HMA surface
