Bedding Sand vs. Joint Sand — They're Not the Same
Bedding sand is the 1-inch layer of washed concrete sand (ASTM C33) screeded flat over your compacted gravel base. Its angular grains lock together under the pavers and let water drain through. Never substitute fine play sand or stone dust — both hold water and migrate, which is how patios develop dips.
Polymeric joint sand is swept into the gaps between laid pavers, then misted with water. The polymer binders harden into flexible joints that resist weeds, ants, and washout. Coverage per 50 lb bag varies enormously with joint width: tight-jointed concrete pavers stretch a bag to 75+ sq ft, while irregular flagstone with wide joints can eat a bag every 20–30 sq ft.
Sand Quantities Quick Reference
| Patio size | Area | Bedding sand (1 in) | Polymeric bags (standard joints) |
|---|---|---|---|
| 10 × 10 ft | 100 sq ft | 0.31 yd³ | 2 |
| 12 × 12 ft | 144 sq ft | 0.44 yd³ | 2 |
| 12 × 16 ft | 192 sq ft | 0.59 yd³ | 3 |
| 16 × 20 ft | 320 sq ft | 0.99 yd³ | 5 |
| 20 × 24 ft | 480 sq ft | 1.48 yd³ | 7 |
Bedding sand is far cheaper in bulk: a cubic yard delivered typically costs less than the equivalent ~54 bags from a big-box store. For anything over about 100 sq ft, order bulk. Need the pavers and gravel base too? Start with the main paver calculator.
Frequently Asked Questions
Do I compact the bedding sand?
No — the bedding sand is screeded loose and level, and the pavers are compacted into it with a plate compactor after laying. Compacting the sand first prevents the pavers from seating properly.
How soon can it rain after applying polymeric sand?
Most brands need 24 hours dry after activation misting. Check the bag — applying polymeric sand to a damp surface or before rain causes hazing and poor curing.
Regular joint sand or polymeric?
Plain concrete sand works and costs less, but washes out and grows weeds. Polymeric costs more per bag but usually lasts years longer between refills. Most homeowners consider it worth the upgrade.