How to Build a Shell Driveway

Insert wooden stakes in the ground to mark the sides of the site. Pull measuring tape across the width to verify that it fits your needs. Shorter driveways with a double garage should be 20 to 24 feet wide to align with the garage. Long driveways should be at least 10 feet wide to accommodate one car at a time. Tie a long string around the stakes to connect them and create an outline of the borders.

Dig out the top layer of grass from between the sides and dump it on a wide tarp near the site to replant in bare areas. Remove the topsoil until the site is at least 1 foot deep and dig the walls straight down with a shovel.

Attach a box scraper to the back of a riding lawn mower. Lift the teeth of the scraper and back the mower to the end of the site by the house. Lower the teeth until they dig 1 inch into the subsoil and set the angle of the blade to about 2 percent, or 1 inch deeper per every 4 feet. This angle will grade the subsoil at a gentle pitch so water drains toward the street.

Drive the mower slowly down the site so the teeth can loosen and spread the dirt evenly. Go over the subsoil twice with a compactor machine to make it as firm as possible. Lay geotextile fabric over the soil to help support the gravel base.

Dump a 4-inch layer of 1 1/4 inch angular gravel over the site and compact it.

Add two 3-inch layers of 3/4-inch angular gravel, and compact the first layer before adding the second.

Drive the mower over the gravel base. Keep the angle set at the same angle as before and position the teeth to dig 1 inch into the gravel. Push the compactor over the gravel base two or three times to pack the base down with as little space as possible between the rocks.

Fill the remaining 2-inch expanse with crushed shells. Rake them evenly over the surface to spread them into edges and corners. Push the compactor over the shells once. Add another 2 inches of shells down the center of the length of the driveway and rake them into a smooth arch with the peak running down the middle.