Paver Base: What It Is, Paver Base vs Sand, and How Much You Need
Paver base is the compacted crushed-stone layer under pavers; paver sand is the 1-inch bedding on top. See recommended paver base depths for patios, walkways and driveways, what material to use and how to calculate how much paver base you need.
Nestiex Team ·
Paver base is the layer of compacted crushed stone that sits under a paver patio, walkway or driveway. It carries the load and drains water. It is the main reason a paver surface stays flat for decades instead of sinking and heaving.
This guide explains:
- what paver base material is,
- how it differs from paver sand,
- how deep it should be, and
- how to calculate how much you need.
For an instant estimate, use the paver base gravel calculator.
What is paver base?
Paver base is a granular, compactable aggregate. Unilock’s tech guide specifies 3/4-inch crusher run gravel or 3/4-inch clear stone (Unilock Basic Tech Guide).
- Crusher run (also called dense grade, #411 or road base) is crushed stone mixed with fines. It compacts into a very firm layer.
- Clear stone (such as #57) has no fines. It compacts less, but drains much faster.
Unilock’s DIY guide warns against stone dust or limestone screenings as a base, because the fines trap water (Unilock DIY guide).
Paver base vs paver sand
These are two separate layers, and you need both:
| Paver base | Paver sand (bedding layer) | |
|---|---|---|
| What it is | Compacted crushed stone | Coarse sand or 1/8” chip |
| Where it goes | Directly on the compacted soil | On top of the base, under the pavers |
| Thickness | 4–14 in depending on use | About 1 inch |
| Job | Carries load, drains water | Gives a smooth, adjustable bed |
| Compacted? | Yes, in thin layers | No, it is screeded flat and left loose |
Unilock’s tech guide calls for “a 1-inch thick bed of coarse sand or a 1/8-inch open-graded chip”. Its DIY guide adds that the bedding layer should not be compacted before the pavers go down.
How deep should paver base be?
Unilock gives two sets of ranges:
| Use | Unilock DIY guide | Unilock Basic Tech Guide |
|---|---|---|
| Patios and walkways | 4–6 in | 6–8 in |
| Driveways | 8–12 in | 10–14 in |
Go to the deeper end if your soil is clay, drains poorly or freezes hard. Unilock notes that clay bases need deeper excavation for drainage.
Other base rules from Unilock
- Compact in lifts. Compact in layers of 2–3 in (tech guide) or 3–4 in (DIY guide). A plate compactor won’t compact more than about 4 inches at once.
- Slope for drainage. Use 1–2% away from the house. That is about ½ inch of fall over 4 feet for 1%.
- Extend the base past the edge. Go beyond the paved area by a distance equal to the base depth. A 20 × 10 ft patio with a 6-inch base is excavated to 21 × 11 ft.
How much paver base do I need?
Cubic yards = length (ft) × width (ft) × base depth (in) ÷ 324
Use the excavated size, including the extension past the edge, not just the paver area.
Example: a 20 × 10 ft patio with a 6-inch base
- Excavated area: 21 × 11 = 231 sq ft
- Base: 231 × 6 ÷ 324 = 4.28 cubic yards
- Tons: 4.28 × 1.4 ≈ 6.0 tons. Typical dry gravel is about 105 lb/ft³ (Engineering ToolBox). Dense-graded base often weighs a little more once compacted, so confirm with your supplier.
- Add 10–15% for compaction loss: about 6.6–6.9 tons.
Bedding sand for the same patio (1 inch over 20 × 10 ft): 200 × 1 ÷ 324 = 0.62 cubic yards.
Paver base quantity chart
| Patio size | 4 in base | 6 in base | 8 in base |
|---|---|---|---|
| 10 × 10 ft | 1.23 yd³ | 1.85 yd³ | 2.47 yd³ |
| 12 × 12 ft | 1.78 yd³ | 2.67 yd³ | 3.56 yd³ |
| 16 × 16 ft | 3.16 yd³ | 4.74 yd³ | 6.32 yd³ |
| 20 × 20 ft | 4.94 yd³ | 7.41 yd³ | 9.88 yd³ |
Paver area only. Add the edge extension and 10–15% for compaction.
Paver base for a driveway
Driveways carry far more weight, so the base must be much thicker:
- 8–12 inches (Unilock DIY guide)
- 10–14 inches (Unilock tech guide)
A 20 × 20 ft paver driveway with a 10-inch base needs about 12.3 cubic yards (17 tons) of base before the edge extension. That is a bulk-delivery job, not a bagged one.
Bagged paver base vs bulk
Big-box stores sell bagged “paver base”, typically a crushed-stone blend. It is convenient for very small patios, but the bag count climbs fast. A 6-inch base for a 12 × 12 ft patio is 72 cubic feet, which is 144 bags of 0.5 ft³. See how many bags of gravel you need and the gravel cost guide for bulk prices.
Step-by-step: preparing a paver base
- Mark the area, adding the edge extension on every side.
- Excavate to: base depth + 1 inch of bedding + paver thickness.
- Compact the soil and set the 1–2% slope.
- Lay geotextile fabric if the soil is soft or clay.
- Spread the base in 2–4 inch lifts, compacting each one.
- Screed 1 inch of bedding sand, and do not compact it.
- Lay the pavers, install edge restraint, then compact and sweep in joint sand.
Frequently asked questions
What is paver base made of? Crushed stone, usually 3/4-inch crusher run (with fines) or 3/4-inch clear stone (Unilock).
What is the difference between paver base and paver sand? Paver base is the thick, compacted stone layer that carries the load. Paver sand is a 1-inch, uncompacted bedding layer the pavers sit on.
How much paver base do I need for a patio? Patio length × width × base depth (in) ÷ 324 gives cubic yards. Use 4–8 inches of base for patios.
Can I use stone dust as paver base? Unilock advises against stone dust or screenings as a base because the fines trap water.
Sources
- Unilock, Basic Tech Guide: unilock.com
- Unilock, Do’s and Don’ts of Paver Installation: Base Preparation: unilock.com
- Engineering ToolBox, Dirt and Mud – Densities: engineeringtoolbox.com