How Much Polymeric Sand Do I Need? (and How to Apply It)
Bags of polymeric sand for common patio sizes, why paver size and joint width change the number, and how to install it without haze.
Polymeric sand is the finishing touch on a paver patio. Swept into the joints and wetted, it hardens enough to resist washing out, weeds and ants, while still flexing a little. How much you need depends far more on your pavers than on your patio’s size.
Why paver size matters
Smaller pavers mean more joints per square foot, and more joints means more sand. A patio of 4” × 8” bricks needs roughly twice as much as the same patio in large slabs. Wider and deeper joints, like those in tumbled or natural stone, use more again.
Rough coverage per bag
| Paver | Approximate coverage |
|---|---|
| 4" × 8" brick paver | about 35 sq ft |
| 6" × 9" rectangle | about 45 sq ft |
| 12" × 12" square | about 60 sq ft |
| 16" × 16" slab | about 75 sq ft |
These are planning figures. Each brand prints its own chart by joint width and paver size; use that once you’ve chosen a product.
Bags for common patio sizes
Bags at the rough coverage above, rounded up. Common bags are around 50 lb; check yours.
| Patio | 4” × 8” | 6” × 9” | 12” × 12” | 16” × 16” |
|---|---|---|---|---|
| 10 × 10 ft | 3 | 3 | 2 | 2 |
| 12 × 12 ft | 5 | 4 | 3 | 2 |
| 12 × 16 ft | 6 | 5 | 4 | 3 |
| 16 × 20 ft | 10 | 8 | 6 | 5 |
| 20 × 20 ft | 12 | 9 | 7 | 6 |
Buy one extra bag. Running out halfway means a visible difference in joints filled on different days.
How to apply it
Always follow the instructions on your bag: products differ in how much water they need and how long they must stay dry. The general method:
- Start with dry pavers and dry joints, on a day with no rain forecast. Manufacturers give a rain-free window and a minimum temperature for each product.
- Compact the pavers first with a plate compactor (with a pad) so they’re fully settled.
- Pour the sand on and sweep it into the joints from several directions. Run the compactor over again to settle it, then top up.
- Fill to just below the top. Alliance Gator, for example, specifies filling to ⅛” below the paver surface (or below the chamfer).
- Clean the surface completely. Sweep with a fine broom, then use a leaf blower until no dust rises. Any grains left on the surface can bond and leave a haze.
- Water as directed, usually a gentle shower in small sections, without washing sand out of the joints.
- Keep traffic off until it’s set. Alliance Gator allows foot and vehicle traffic after 24 hours if dry.
If it goes wrong
- White haze on the pavers: usually from dust left on the surface or from wetting damp pavers. Haze removers and efflorescence cleaners are sold for this.
- Sand washing out: too little water, joints not filled deep enough, or rain arriving too soon.
- Soft or crumbly joints: not enough water to activate the binder through the full depth.
Learn the full build in How to Build a Paver Patio. The Paver Patio Planner estimates polymeric sand with everything else, and lets you enter the coverage from your own bag.