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How many bags of polymeric joint sand you need, from paver size, joint width, and depth.
With these inputs:
| Result | Value |
|---|---|
| Polymeric sand | 8 bags (50 lb) |
| Weight | 387 lb |
| Coverage per bag | 28 sq ft |
| Cost | $200 – $360 |
| Patio area | 200 sq ft |
| Paver | 4" × 8" |
| Joint width × depth | 0.25" × 2.25" |
| Joint volume | 3.9 cu ft (incl. 10%) |
| Bags (50 lb, ~0.5 cu ft) | 8 bags |
Sweep the sand in dry, compact with a plate compactor fitted with a pad, top up, then blow the surface clean before misting. Any haze left on the paver face hardens permanently.
The coverage printed on a bag of polymeric sand assumes one paver size and one joint width. This calculator works from your actual pavers: it measures the total joint length per square foot, multiplies by joint width and depth, and tells you how many 50 lb bags to buy for your patio.
A 50 lb bag covers about 60 to 75 square feet of 4 by 8 inch pavers with tight 1/8 inch joints, but only 25 to 40 square feet with 1/4 inch joints, and far less with the wide joints of tumbled or natural stone. Joint width is the biggest variable.
It should fill the joint to within 1/8 inch of the top of the paver, and the joint must be at least 1.5 inches deep for the binder to hold. Shallow joints, such as over a mortar bed, need a different product.
Only after you remove the old joint sand to at least 1 inch deep, ideally the full paver depth. A thin skin of polymeric sand over loose sand cracks and lifts within a season.
Most products take foot traffic after 24 hours and vehicles after 48 to 72 hours. Rain in the first few hours after misting can wash the binder out, so check the forecast before you start.
Need the whole roof at once? The free roofing calculator works out roof area, squares, shingle bundles, underlayment, drip edge, ridge cap and installed cost from one set of measurements.