Do Pavers Sag With Time?

Depth Perception

• Pavers are typically 2 3/8 inches thick, making them vulnerable to sagging without a thick base. For example, multi-sized crushed rock forms your first layer directly on the excavated soil. Spread these rocks into a 4- to 6-inch-thick layer. A 1-inch layer of sand covers the crushed rocks. Finely level this sand layer to create a firm paver bed. Use a 1-inch-wide electrical conduit tube laid horizontally on the crushed rocks to provide a depth indicator as you spread the sand. Any uneven contours on the crushed rocks or sand base translates to a weak paver surface above.

Vibration Counts

• Compacting your base with a plate compactor creates a uniform surface to prevent sagging. Starting with the excavated soil surface, run the plate compactor across the entire installation site. Compaction tightens up loose soil patches that erode over time. Spread only 2 inches of crushed rock on the compacted soil at a time. Compact each 2-inch layer with the plate compactor until you complete the necessary 6-inch depth. Crushed rock, with its multi-sized gravel, locks into place with the compactor's vibrations.

Material Confusion

• Spread woven geotextile fabric across the compacted and excavated site before spreading crushed rock. This extra base layer prevents sagging, especially if your soil is predominantly sand. Select crushed rock with sharp edges, rather than rounded pellets. Although multi-sized, smooth rocks do not lock properly under compaction and create a potentially weak base. Use concrete sand for your 1-inch bedding layer because of its locking multi-sized particles. Paver joints require a fine sand type, such as play sand, to completely fill in the spaces and avoid sagging.

Joint Bridging

• Wide spaces between pavers causes eventual sagging. Each joint should range between 1/16 and 3/16 inches wide. This critical spacing provides enough area for sand to completely fill the joints and lock into place with compaction. Proper installation includes repeated sand application and compaction to slowly fill the joints with a firm locking action. Filled joints larger than 3/16 inch cannot lock properly. Sand erodes from the joint, causing paver misalignment, chipping and sagging.