Gravel Driveway Materials

Large Gravel

• Large gravel includes crushed rocks that measure more than 1 1/4 inches. Typically used as inorganic mulch, it improves drainage, because the large gaps between the rocks enable water to escape with ease. If a yard has clay or sandy soil, a thin, compacted layer of large gravel over the bottom of the site will reinforce top layers of gravel so they don't sink.

Medium Gravel

• Medium gravel is crushed into irregular shapes with sharp ends that naturally wedge together under pressure. It measures between 1 1/4 and 3/4 inches and enables underground moisture to escape while also compacting into a stable base strong enough to withstand heavy weight. Use medium gravel for an 8-inch-thick center of the driveway. For best results, add it in small amounts at a time and compact it as you go.

Small Gravel

• Small gravel includes rocks under 3/4 inch, as well as those that have broken down into a sandlike consistency. Tamp this material down to form a nearly solid layer that's ideal for resisting erosion. To complete a gravel driveway, add a 2-inch layer of small gravel on top, then even it out and compact it. Add another 2-inch layer in the middle, and spread it into a crown so water will flow toward the sides.

Landscape Fabric and Edging

• Two optional but useful materials to use on a gravel driveway are landscape fabric and edging. The fabric is designed to block underground weeds and prevent loose dirt from pulling foundation gravel down. Fit fabric across the bottom and side walls of the driveway site and pin it in place with spikes. Once the driveway is installed, add edging to contain the gravel and block wayward growth from encroaching. Use timber or medium stones to complement the casual style, or add definition with bricks or metal edge restraints.