What Is the Purpose of Crushed Limestone?

Foundation

• Crushed limestone ranges in size from 1 to 1 1/2 inches thick. It is broken down into irregular shapes with edges that will wedge together when compacted. Crushed limestone also contains stone dust, which fills some of the crevices between the larger stones creating a solid base. Once compacted, the narrow crevices allow moisture to escape. The foundation is also flexible enough to absorb tension when the ground freezes, which prevents cracking and frost heave damage.

Driveway

• A simple alternative to dirt and pavement, a crushed limestone driveway is simple to install and maintain. It forms a water permeable surface that allows water runoff to escape, preventing mud, puddles and other eyesores. Do-it-yourselfers can lay crushed limestone directly over dirt or dig out the site so the surface sits level with the ground. Install edge restraints or a border of medium-sized fieldstones to contain the limestone and block encroachment.

Backfill

• Dry-stacked stone retaining walls are typically recessed into the soil it is retaining by about an inch for every row of stones. Backfilling with crushed limestone reinforces the wall and provides a barrier that retains soil while still allowing moisture to escape. To backfill, pack crushed limestone into the space between the wall stones and the soil after setting each row.

Setting Posts

• To prevent frost heaves from occurring, fence posts are typically set in crushed rock or quick-setting cement. The stone dust in crushed limestone clings to the rocks when wet and hardens like cement as it dries. To secure fence posts in an area prone to freezing temperatures, dig post holes an extra 6 inches deep with a wider bottom to anchor the base. Add 6 inches of crushed limestone and tamp it down. Set the post in the center of the hole, then fill around it with more crushed limestone. Moisten the material and pack it down until it forms a slight mound around the base about 1 inch above ground level.