How to Level Out a Slope for a Driveway
While all driveways should be laid with a proper slope for drainage, a steep decline will pose a hazard in bad weather. If your home is on a hill, leveling out the site allows you to build up a solid, uniform foundation. This project can be done manually, but it’s worth renting the right equipment to reduce labor and ensure consistent results over the whole site.
Lay down parallel ropes to mark the course of the driveway. Measure the width using a tape measure, and move the ropes as needed to make the width 10 to 16 feet to fit one or two cars, respectively.
Cut off the top layer of grass with a shovel, and dump it on a tarp to replant over bare spots. Use an excavator machine or a shovel to dig out 12 inches of soil from between the two ropes. Pile the soil on a tarp to use over unwanted low areas in the yard.
Attach a box scraper to the back of a lawnmower tractor. Set the angle of the blade at zero. Drive the tractor slowly from one end of the driveway to the other. The blade will cut into high areas and disperse it evenly over low areas of the yard. Lift the blade and back out of the site.
Repeat this step three times or until the subsoil reads level. Lay a board on the soil and place a 4-foot bubble level on top of it. The site is level when the bubble rests at the center when placed in each section of the driveway.
Go over the subsoil with a compactor machine until it feels firm.
Build up the gravel foundation by spreading three 3-inch layers of 3/4-inch aggregate over the site and compacting between each layer.
Establish a slight slope for drainage by setting the angle of the box scraper at 1/4 inch per foot. Drive the tractor from the end of the site by the house, and then drive it slowly to the end so the base will angle downward toward the street, and compact the base again.
Lay the driveway surface over the compacted base. For a gravel driveway, spread a 4-inch layer of small gravel into a crown so the sides will be lower than the center. With pavers, bricks or flagstones, you’ll need to spread a 1-inch-thick sand bed, and then set the individual pieces in your planned pattern.