Quick answer: a paver patio is a three-layer system: compacted soil, a compacted aggregate base, and a 1 inch bedding sand layer under the pavers. The Interlocking Concrete Pavement Institute (ICPI) Tech Spec 2 calls for a base at least 4 inches thick for patios and 6 inches for residential driveways, with the bedding layer about 1 inch of ASTM C33 concrete sand. For a 200 ft² patio that is about 0.62 yd³ of sand and 2.5 yd³ of base stone before the extra allowance.
Use the Paver Base Calculator, Sand Calculator and Gravel Calculator for your exact area. Here is how to check the numbers.
What each layer does
| Layer | Typical depth | Purpose |
|---|---|---|
| Pavers | by product | The wearing surface |
| Bedding sand | ~1 in | Levels the pavers and lets them settle evenly |
| Aggregate base | 4 in (patio), 6 in (driveway), minimum | Carries load and drains |
| Compacted soil | The foundation of everything above |
These minimums come from ICPI Tech Spec 2 (construction of interlocking concrete pavement), which the Concrete Masonry & Hardscapes Association also references in its paver guide specifications. Weak soils, heavy loads and freezing climates need thicker bases. Ask a local pro or the paver manufacturer.
Sand: what kind
ICPI specifies bedding sand that meets ASTM C33 (concrete sand), clean and sharp rather than rounded. Do not use stone dust or fine masonry sand for the bedding layer. Keep it about 1 inch thick, and don’t use it to fill low spots in the base: fix those in the base itself.
Compaction
ICPI calls for compacting the aggregate base to about 98% of standard Proctor density. Practically, that means using a plate compactor in thin lifts (several passes per layer) rather than dumping the whole depth at once. Compact the soil first.
The formulas
Sand (yd³) = area (ft²) × 1 in ÷ 12 ÷ 27
Base (yd³) = area (ft²) × base depth (in) ÷ 12 ÷ 27
Add ~10% for waste and compaction
Worked example: a 200 ft² patio
- Bedding sand (1 in): 200 ÷ 12 ÷ 27 = 0.62 yd³. With 10%: 0.68 yd³.
- Base (4 in): 200 × 4 ÷ 12 ÷ 27 = 2.47 yd³. With 10%: 2.72 yd³.
- Driveway version (6 in base): 3.70 yd³, or 4.07 with 10%.
Weight matters when you haul it. Sand and crushed stone commonly weigh around 2,500 to 2,900 lb per yd³ (North Bay Materials), so the 0.62 yd³ of sand is roughly 1,700 lb, and 2.47 yd³ of base stone is about 3.3 tons at about 2,700 lb per yard. See our cubic yards to tons guide.
Joint sand
After pavers are laid, sweep sand into the joints to lock them. Use the type the paver manufacturer recommends, such as jointing sand or polymeric sand. The volume is small compared with the bedding layer, so buy by the bag: manufacturers list coverage per bag for their product.
Edge restraints
Pavers move without a restraint. Install an edge restraint all around, as ICPI describes, and set it on the compacted base before you spread the sand.
Common mistakes
- Using a thin base. The base is what keeps pavers from sinking.
- Making the sand layer thick. More than about 1 inch can cause settling and rutting.
- Compacting the sand before screeding. Level the bedding sand, then set pavers. Compact after laying.
- Using the wrong sand. Concrete sand (ASTM C33) for bedding; jointing sand for joints.
- Forgetting drainage. Slope the surface away from buildings so water runs off, and follow the slope your paver manufacturer or local code specifies.
Frequently asked questions
How much sand do I need for 100 sq ft of pavers?
100 ÷ 12 ÷ 27 = 0.31 yd³ at 1 inch.
How thick should the gravel base be?
At least 4 inches for patios and walks, and 6 inches for residential driveways (ICPI), more for poor soil or freezing climates.
Can I put pavers directly on sand?
No. The aggregate base carries the load. Sand alone will shift and settle.
How many tons of base stone for a 200 ft² patio?
About 3.3 tons at 4 inches, using roughly 2,700 lb per yd³. Confirm the weight with your supplier.
Sources
- Interlocking Concrete Pavement Institute, >Tech Spec 2: Construction of Interlocking Concrete Pavements: base thickness, bedding sand, compaction, edge restraints.
- Concrete Masonry & Hardscapes Association, >Guide Specification PAV-GSP-011-21: paver installation specification.
- North Bay Materials, >Landscape Materials Density Chart: weights of sand and stone.
Planning guidance only. Follow the paver manufacturer’s installation instructions and local conditions.