Concrete Driveway Requirements

Preparation

• The surface area must be properly prepared in order to pour a concrete driveway. The homeowner should determine whether the driveway needs to be wide enough for a single car or for two cars. According to the Portland Cement Association, a single car driveway should be between 8 and 9 feet wide. Driveways should be at least 15 feet wide to accommodate two cars parked side by side. Any existing surface must be removed, the area must be excavated to the appropriate depth and a gravel base should be laid and compacted. Cement forms should be installed at a depth to match the sidewalk or connecting street as well as the garage or carport.

Thickness

• Homeowners should contact their local building-code department for any specific requirements regarding materials used to build a concrete driveway. According to the Community Development/Building Department of Darien, Ill., concrete driveways must have a 4-inch base of compacted grade eight stone beneath 5 inches of concrete between the sidewalk and the home. The apron area between the sidewalk and the street requires 6 inches of concrete. According to Concrete Forever contractors, national building codes recommend 6 inches of concrete for areas of the driveway that use steel reinforcement rods.

Materials

• Driveway concrete mixtures will vary based on location and climate. Recommended specifications for concrete driveways are detailed at ASTM C-94 of the American Standards for Testing and Materials. Ready-mixed concrete should be rated at 4,000 PSI compression strength with an air content of between 5 and 7 percent, according to the Portland Cement Association. Slump, which is a measure of concrete consistency, should be specified at 4 inches, according to Concrete Forever contractors. Aggregate should be no larger than 1 inch.