How to Spread Road Base
Road base is a mixture of sand, soil, aggregates and moisture. Spread and compacted road base provides a foundation for asphalt, concrete, stone and tile. Road base is a critical component of road and driveway construction and is also used under building foundations and walls. A proper foundation of road base requires level spreading and dense compaction. Regardless of the size or scope of a project, these two priorities remain constant
Estimate the number of yards of road base required for the project. Multiply the length of the project by the width to find the area. Convert the area to feet and inches. Multiply the area by the depth required. For roads and parking lots -- heavy traffic sites -- 4 to 6 inches of depth is required. For patios, driveways and foundations, 2 to 3 inches of depth will suffice. Road base is delivered in square yards. There are 1,296 square inches in a square yard. Divide the area and depth sum by 1,296 to find the number of yards. For example, the sum of 360, multiplied by 120, multiplied by .5 -- the decimal equivalent of 6 inches -- divided 1,296 equals 17.1: the number of square yards required to base a parking lot the size of a football field.
Set up a laser level for projects that require a constant elevation. Excavate the site flat with an implement or pick and shovel. Walk the site with the laser level and check grade. Reduce the elevation of any high-high spots to grade.
Dump a truckload of road base at one edge of the site. Level it with a machine or a shovel and rake. Reduce the depth to 2 inches. Compact the road base with a sheep's foot or a plate compacter. Make 10-20 passes over every inch of the road base to assure the compaction density is sufficient. Cover the entire area of the site, then repeat the process on the second lift of road base. Continue leveling and compacting the road base until it is the required depth.
- Bulldozer, backhoe, excavator, front-end loader or shovel and rake
- Laser level
- Sheep's foot compacter or plate compacter