Paver Base & Sand Calculator
Calculate Patio Sub-Base Gravel, Bedding Sand & Polymeric Joint Sand
The secret to a paver patio that doesn't sag or become wavy over time lies entirely in the underground foundation layers. A proper paver layout requires a compacted gravel sub-base, a level sand bedding layer, and polymeric joint sand to lock pavers in place. Use this calculator to estimate material volumes and weight in tons for your layout.
What Is a Paver Base and Why Does It Matter?
To build a paver walkway, driveway, or patio, you must excavate the soil and build a layered foundation. The primary base layer consists of **crushed aggregate gravel** (usually 3/4-inch crushed stone with fines, known as Road Base or Quarry Process). Once compacted, this layer provides a rigid structural deck that drains water and resists wheel load pressure.
Directly above the compacted gravel is a **1-inch bedding sand layer** (washed concrete sand). The bedding sand acts as a smooth cushion for paving stones, allowing you to hammer pavers flat and level. Finally, **polymeric joint sand** is swept into the cracks between the pavers. Once misted with water, polymers activate, locking pavers together like a single structural grid and preventing weeds and ants from invading joints.
Skipping any of these base specifications will result in pavers shifting, tilting, or sinking. For sandy soils, 4 inches of gravel base is sufficient; clay soils or driveway installations require 6 to 8 inches of gravel base.
Paver Patio Base Layer Specifications
| Patio Base Layer | Standard Material Name | Recommended Depth | Primary Function |
|---|---|---|---|
| Sub-Base Layer | 3/4" Crushed Road Base | 4 - 6 inches | Load bearing support, drainage, structure |
| Bedding Layer | Washed Concrete Sand | 1 inch | Levelling cushion, paver seating |
| Joint Filler | Polymeric Jointing Sand | Full joint height | Paver lock, sweeps weed growth and ant holes |
| Geotextile fabric | Non-woven Filter Fabric | Under gravel base | Soil stabilization, weed prevention |
How to Use This Paver Base Calculator
Input your total patio square footage (measured by multiplying length times width). Select your gravel sub-base and bedding sand depths. Provide local unit costs per ton for aggregates and sand, and the cost of a 50lb bag of polymeric sand. Click Calculate to output estimates.
Frequently Asked Questions
Can I use stone dust instead of bedding sand?
No. Most professional hardscaping bodies (such as the ICPI) advise against using stone dust for bedding. Stone dust retains moisture and degrades over time, which causes paver shifting and efflorescence (white mineral stains on pavers).
How much does polymeric sand cover?
A standard 50-pound bag of polymeric joint sand covers approximately **50 to 75 square feet** for standard pavers with narrow joints (1/8 inch wide). Wider joints or irregular cobbles will reduce coverage to 20-30 sq ft per bag.
Do I need to compact the gravel base?
Yes. The gravel base must be compacted in 2-inch layers using a mechanical plate compactor. Uncompacted gravel will settle under pedestrian traffic, resulting in a sunken, uneven patio.
- Interlocking Concrete Pavement Institute (ICPI) - Standards for paver base construction and aggregate gradations.
- ASTM International - ASTM C33 sand specs and ASTM D448 gravel grading standards.