Polymeric Sand Calculator
Estimate polymeric sand bags from paver geometry and product yield, then test how joint width and installation conditions affect the plan.| Measure | Value | Planning use | Copy |
|---|---|---|---|
| {{ row.measure }} | {{ row.value }} | {{ row.use }} |
| Check | Status | Evidence | Next action | Copy |
|---|---|---|---|---|
| {{ row.check }} | {{ row.status }} | {{ row.evidence }} | {{ row.action }} |
Chart unavailable. The calculated data remains available as CSV.
Polymeric sand fills the joints between dry-laid pavers and is activated with water after the surface has been swept clean. A takeoff must estimate the empty joint space, not just the paved area. The same patio can need very different quantities when paver size, joint width, fill depth, or pattern changes.
Small pavers create more joint line per square metre than large slabs. Wide or deep joints increase the cross-section of every line. Curves, borders, diagonal patterns, tumbled edges, and uneven reclaimed units make the field less regular, while sweeping and compaction create jobsite loss. Bag count therefore combines geometry with a deliberate allowance and the actual product's usable yield.
Bag weight and bag yield are not interchangeable. Weight identifies the package, but yield tells how much joint volume that package can fill under stated conditions. Coverage charts often change with joint dimensions and paver shape. The current technical data sheet should override a generic volume assumption or preset.
Quantity is only one part of a successful installation. Joint width and depth must suit the product. The joints need proper cleaning and compaction, drainage must be adequate, and temperature and dry-weather timing must meet the label. A correct bag count cannot compensate for a shallow joint, trapped water, poor base construction, or premature rain.
- Measure the finished paver field and exclude openings that contain no joints.
- Use the visible face dimensions of a representative paver, not a nominal module that includes the joint.
- Measure the cleaned fill depth that will actually receive sand, not the full paver thickness.
- Separate mixed-size zones, borders, or sharply different joint widths when one representative geometry would hide important variation.
How to Use This Tool:
Build the takeoff from the finished footprint, representative paver geometry, measured joints, and the product's own yield.
- Choose a Footprint method and enter rectangle dimensions, a circle diameter, or a measured area from the plan or site.
- Select a Paver face or enter the visible length and width of one representative paver.
- Choose the layout regularity, then enter the average Joint width and cleaned Joint fill depth.
- Select a bag profile or enter the current product's yield and package weight. Add a waste allowance for sweeping, cuts, irregular joints, and site variation.
Use yield or coverage from the current product data sheet for the measured joint geometry. Bag weight alone does not determine coverage.
- Review exact bags, whole bags, order volume, and leftover volume. Use the joint-width scenarios to see how measurement uncertainty changes the order.
- Optionally enable installation-condition checks and compare width, depth, recess, drainage, temperature, and forecast dry time with the actual product instructions.
Interpreting Results:
Order volume is the estimated joint-fill volume after the waste allowance. Exact bags divides that volume by the selected yield, while Whole bags rounds upward so the order is not short. Leftover is purchased yield minus order volume.
The joint-width demand scenarios are sensitivity checks, not separate recommendations. A 35% wider joint produces 35% more modeled volume because the other assumptions stay fixed. If a plausible width change crosses a whole-bag boundary, remeasure several representative joints before buying.
A passing readiness profile means the entered conditions meet the selected planning thresholds. It does not confirm base drainage, installation technique, forecast reliability, surface compatibility, or the requirements of a different product.
Technical Details:
The model treats the paver field as a rectangular grid of representative faces. Joint-line density increases as paver length or width decreases. A layout multiplier raises the line estimate for staggered, diagonal, curved, bordered, or irregular arrangements.
Formula Core:
After all lengths are converted to metres, total joint line J is estimated from field area A, paver length L, paver width W, and layout multiplier m.
Here w and d are joint width and depth in metres, q is the waste percentage, and Y is yield in litres per bag. Multiplying cubic metres by 1,000 gives litres. Whole-bag rounding is always upward, with at least one bag for a valid positive project.
| Layout | Multiplier |
|---|---|
| Stack bond or straight grid | 1.00 |
| Running bond | 1.03 |
| Herringbone or diagonal | 1.08 |
| Curves, border, or inlay | 1.16 |
| Irregular or tumbled joints | 1.22 |
These multipliers are planning assumptions, not manufacturer coverage claims. A measured-area footprint changes only the field area; it does not measure joint density directly. Mixed paver kits and wide border joints can depart materially from the representative grid.
Rule Core:
The optional readiness check compares the entered conditions with the selected profile. Joint width is always evaluated; recess, drainage, temperature, and forecast dry time are marked not evaluated until readiness is enabled.
| Profile | Joint width | Minimum depth | Minimum recess | Minimum temperature | Dry hours |
|---|---|---|---|---|---|
| Generic 25 kg or 50 lb | 3 to 50 mm | 38 mm | 3 mm | 0 °C | 1 |
| Fine-joint planning | 2 to 25 mm | 25 mm | 3 mm | 5 °C | 3 |
| Wide-joint planning | 5 to 50 mm | 20 mm | 3 mm | 5 °C | 4 |
Width passes when it is at least the profile minimum and no more than the maximum. Depth, recess, temperature, and forecast dry time pass at equality or above. Drainage only records whether a positive slope was entered. Any failing enabled check changes the overall result to review conditions; none of these checks changes the bag count.
Limitations and Accuracy Notes:
- Manufacturer coverage charts and installation instructions override every generic yield, layout multiplier, and readiness profile.
- The grid estimate does not directly model chamfers, permeable joints, voids, mixed sizes, edge restraints, compaction density, or sand remaining from an earlier installation.
- Required dry time, temperature, watering, and cure conditions vary by product and weather. Check the current technical data sheet and forecast immediately before installation.
Worked Examples:
Twenty-square-metre running-bond patio
A 20 m² field of 200 × 100 mm pavers, 5 mm joints, 40 mm fill depth, and the 1.03 running-bond multiplier produces 309 m of modeled joint line and 61.8 L of base volume. A 12% allowance raises the order to 69.216 L. At 15.5 L per bag, the exact need is about 4.47 bags, so the order rounds up to 5 bags with about 8.28 L of modeled yield left over.
References:
- SmartSand Polymeric Sand Technical Data Sheet, Techniseal.
- NIST Guide to the SI, Appendix B: Conversion Factors, National Institute of Standards and Technology.