Overfilling or under-filling paver joints with polymeric sand can lead to project failures. When installing polymeric sand, one of the most important steps is properly compacting the sand into the joints, preferably with a vibratory plate compactor. Once initial compaction is complete, the height of the sand will drop by 30-50%. Be sure to sweep in more sand to fill the joints up to 1/8 inch (3mm) below the paver’s edge or chamfer.

To start filling paver joints with polymeric sand, spread the sand across the surface with a hard-bristle broom. During this process, ensure the sand completely fills the joints. Joints must be clean because if there’s any residual material between them, it will have to be completely removed. It’s also important never to mix different types of material within the joints. When you sweep, leave a layer of sand on the surface to enhance vibration and to better consolidate product into the joints.

Next, use a vibratory plate compactor to vibrate the sand into the paver joints. Always use a rubber pad to protect the paver surface. A roller compactor is recommended for slab installations.

Fill the joints up to 1/8 inch (3mm) below the paver’s edge or chamfer. Compact in several directions to eliminate air gaps or voids in the joints. Repeat the sweeping and compacting until joints are filled and consolidated. Pay particular attention to narrow joints, which require more effort to completely fill.

Avoid using excessive force when doing the final sweep of excess polymeric sand from the surface. Aggressive sweeping can push sand out of the joints and leave inadequate product to set up properly. When doing a first pass sweep to remove excess product from the surface, use a hard-bristle broom, followed by a soft-bristle broom. Always ensure the height of the polymeric sand is at least 1/8 inch (3mm) below the edge or paver or chamfer.