Paver Base Gravel: What You Need Under Patios, Walkways & Driveways
The base layer under your pavers determines whether your patio looks beautiful for 20 years or starts shifting and cracking within 3. Get the base right and the rest takes care of itself. Skip it or do it wrong and you're resetting pavers every few years.
Here's exactly what you need and how to do it.
Why the Base Matters So Much
Pavers themselves are strong. But they're only as stable as what's underneath them. Without a properly prepared base:
- Pavers sink unevenly as soil settles under vehicle or foot traffic
- Frost heave lifts and tilts pavers in our occasional western Washington freezes
- Poor drainage causes water to pool under the surface, softening the base
- Weeds push up through poorly compacted material
A proper crushed rock base eliminates all of these problems.
The Standard Paver Base System
Layer 1: Compacted Subgrade
Native soil, excavated and compacted. The foundation. Any soft spots here must be fixed before adding base material.
Layer 2: Crushed Rock Base (4-8 inches)
The most important layer. Use 3/4" minus crushed rock (road base/crusher run). This material contains a mix of angular crushed rock and fine particles that compact into a hard, stable surface.
- Walkways and patios: 4 inches compacted depth
- Driveways (passenger vehicles): 6 inches compacted depth
- Driveways (heavy vehicles/RVs): 8-10 inches compacted depth
Layer 3: Bedding Sand (1 inch)
Coarse concrete sand (not play sand — too fine). Screeded to exactly 1 inch depth. Provides the final leveling bed for pavers to sit in. Do not compact the sand before laying pavers — it needs to remain loose so pavers can be pressed into it for leveling.
Layer 4: Pavers
Set in the sand bed, tapped level with a rubber mallet. Joints filled with polymeric sand after installation.
Crushed Rock Calculator for Paver Base
Length (ft) × Width (ft) × Depth (inches) ÷ 324 = Cubic Yards
Add 10-15% for compaction loss.
| Project Size | 4" Base | 6" Base | 8" Base |
|---|---|---|---|
| 100 sq ft patio | 1.4 yds | 2.1 yds | 2.8 yds |
| 200 sq ft patio | 2.8 yds | 4.1 yds | 5.5 yds |
| 400 sq ft patio | 5.5 yds | 8.3 yds | 11.1 yds |
| 10×60 ft driveway | 7.4 yds | 11.1 yds | 14.8 yds |
| 12×60 ft driveway | 8.9 yds | 13.3 yds | 17.8 yds |
Why 3/4" Minus Is the Right Crushed Rock for Base
You need the "minus" material — not clean crushed rock. Here's why:
- 3/4" minus contains crushed rock ranging from 3/4" down to fine dust. When compacted, the fines fill the void spaces between larger particles, creating a dense, rigid mass.
- Clean crushed rock (no fines) doesn't compact the same way — it stays loose. Excellent for drainage; poor for structural base.
- Pea gravel is round and rolls — completely wrong for paver base. Pavers will shift and sink.
Compaction: Don't Skip This Step
Compaction is what turns a loose pile of crushed rock into a structural base. Without it, pavers settle unevenly within the first year.
- Rent a plate compactor (available at most equipment rental shops)
- Compact in lifts — no more than 4 inches at a time before adding the next layer
- Make 3-4 passes with the plate compactor over each lift
- Wet the crushed rock slightly before compaction — moisture helps the fines bind
- Compact in two directions (lengthwise, then crosswise)
Pacific Northwest Notes
Drainage Slope
Build a 1% cross-slope (1 inch per 8 feet) into your base for drainage. Water on a flat paver surface has nowhere to go — it puddles. A slight slope sheds water to the edges.
Geotextile Fabric Under Base
In our clay soils, lay non-woven geotextile fabric directly on the subgrade before adding base rock. This prevents the crushed rock from slowly mixing into the native clay over time — a process called "pumping" that gradually destabilizes the base.
Frequently Asked Questions
Can I use pea gravel as a paver base?
No. Pea gravel is rounded and doesn't compact into a stable surface. Pavers placed on pea gravel will shift, sink, and become uneven. Use 3/4" minus crushed rock (road base) as your base material.
How thick should the sand layer be under pavers?
Exactly 1 inch of coarse concrete sand. Too thin and you can't achieve a level surface; too thick and pavers sink unevenly under load. The 1-inch bedding layer is standard across all paver installations.
Do I need a base under stepping stones?
For stepping stones in garden areas, a 2-inch sand or fine gravel base is usually sufficient. For stepping stones in a patio or high-traffic walkway, use the full crushed rock base system.
Order paver base rock delivered. Harbor Soils delivers 3/4" minus crushed rock and coarse concrete sand throughout Gig Harbor, Port Orchard, and Kitsap County. Same-day delivery. Order crushed rock → | See our hardscape materials →
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