Is a Good Base Important in Paving a Driveway?

Importance of a Good Base

• A good driveway base provides structural support for driveway surface materials and promotes adequate drainage both above and below the driveway's surface. Structural support ensures that the driveway can accommodate required loads, particularly vehicles or machinery. A strong, stable base prevents heaving, settling and damage to a driveway, such as cracks and uneven surfaces. Additionally, a driveway base constructed of permeable materials prevents water and frost damage below the driveway surface and shapes a slope that sheds water.

Sub-grade

• The term sub-grade refers to the natural surface beneath a driveway or roadway. Driveway construction begins with preparation of the sub-grade surface. Grading contractors typically use heavy machinery to draw wide blades across the sub-grade surface. Grading blades smooth, level or slope the sub-grade material to create a firm foundation for the driveway's sub-base and base layers. A well-prepared sub-grade surface supports sub-base and base materials allows adequate distribution of driveway loads.

Sub-Base and Base

• Driveway sub-base and base layers typically consist of bulk aggregate, including construction gravel, pea gravel and sand. Larger aggregate, such as construction gravel, usually forms the sub-base; the layer that rests rests directly on top of the sub-grade. Many builders lay landscape or filter fabric between the sub-grade and sub-base. Smaller, leveling aggregate typically forms the base layer. The base layer occupies the space between the sub-base and driveway surface material and provides a even surface for the installation pavement materials.

Surface Coverings

• Popular paving materials include concrete, asphalt and pavers. As solid, integral units, concrete slabs and asphalt surfaces are generally more durable than pavers. However, set on a properly prepared base, pavers' durability rivals that concrete and asphalt. Although asphalt accepts paint, concrete and pavers offer the most flexibility for decoration. Pavers are available in a broad range of colors and shapes and concrete accepts paint, stain, stamping and engraving. Regardless of material, a good base reduces cracks and unevenness on a driveway's surface.