Fill Dirt vs Lava Rock
Side-by-side comparison of Fill Dirt and Lava Rock to help you choose the right gravel for your project.
Overview
Subsoil material free of organic matter, used for grading, filling, and raising elevation. Fill dirt is a lower-grade soil that lacks the nutrients of topsoil, making it ideal for structural and non-growing applications where settling must be minimized.
Lava rock is a lightweight, porous volcanic stone commonly used in landscaping. Its rough texture helps retain moisture while allowing airflow to plant roots.
Common Uses
Fill Dirt
- ✓ Grading
- ✓ Filling depressions
- ✓ Raising elevation
- ✓ Backfill
- ✓ Construction site prep
- ✓ Under slabs
Lava Rock
- ✓ Landscaping
- ✓ Garden beds
- ✓ Decorative ground cover
Pros & Cons
Fill Dirt
- + Very affordable — often cheapest material available
- + Compacts firmly for structural support
- + Does not decompose or settle like organic soil
- + Widely available from construction sites
- + Ideal base under gravel or concrete
- − Not suitable for growing plants
- − Must be free of debris and contaminants
- − May contain clay that drains poorly
- − Needs compaction in layers for stability
- − Quality varies widely between sources
Lava Rock
- + Very lightweight
- + Excellent moisture retention
- + Decorative appearance
- − Breaks down over time
- − Sharp edges
- − Can scatter easily
Cost Comparison
| Measure | Fill Dirt | Lava Rock |
|---|---|---|
| Per ton | $5 – $15 | $90 – $150 |
| Per cubic yard | $8 – $25 | $110 – $180 |
Sizes & Colors
Fill Dirt
Fine to coarse soil particles, free of organic matter like roots, grass, or leaves. Color ranges from tan to reddish-brown depending on local geology. "Clean fill" means free of debris, rocks larger than 3", and contaminants.
Lava Rock
Typically 3/4"–1.5" sizes. Red or black.
Published February 11, 2026
Compare prices from local suppliers
Get quotes from gravel suppliers near you to find the best deal.