Polymeric Sand Calculator
Calculate polymeric sand bags needed to fill paver joints.
Enter paver area, joint width, and depth to get bags required and total cost.
Polymeric sand fills the joints between pavers. When wet, the polymers bind into a flexible mortar that locks pavers in place, blocks weeds, and shrugs off ant tunneling. Get the quantity wrong and either you waste expensive sand or you stop halfway through and the joints harden unevenly.
Coverage depends heavily on joint width and paver size. Manufacturers (TechniSeal, SuperSand, EnviroSEAL) publish coverage tables that all roughly agree:
- Standard pavers (4 x 8 in), 1/8 inch joints: 75 to 100 sq ft per 50 lb bag
- Standard pavers, 1/4 inch joints: 50 to 75 sq ft per bag
- Large format (12 x 24 in), 1/4 inch joints: 80 to 100 sq ft per bag
- Wide joints (1/2 inch+, flagstone): 25 to 40 sq ft per bag
- Narrow joints (1/16 inch, cobbles): 100 to 130 sq ft per bag
The formula combines joint volume with paver size:
joint_length_per_sqft = 2 / paver_avg_size (rough rule) joint_volume = length x width x depth bags = (area_sqft x joint_volume_per_sqft) / bag_volume
Most home users do not need to calculate this from scratch. Pick the coverage rate from the table that matches your install and:
bags = ceil(area_sqft / coverage_per_bag x 1.10)
The 10% buffer is non-negotiable. Polymeric sand activates when wet — a bag opened and not used within an hour starts to clump. If you run short mid-job, you cannot just walk to the store and finish two hours later. The first sweep already locked in.
Activation rules:
- Sweep into joints when pavers are dry. Compact with a plate compactor.
- Sweep again, top up, then shower-spray to activate. Heavy hose stream washes the sand out.
- Avoid rain for 24 hours.
- Single-coat depth: 1.5 inches minimum below paver surface, never above.
Bags come in 50 lb (most common) or 35 lb (lighter, easier to lift). Prices run $25 to $45 per 50 lb bag. Cheaper grades (under $25) tend to crumble within two seasons.