The geometric space occupied by the target finished layer.
The default adds 20% of finished volume. Enter a different allowance for your product and site.
Editable loose-density planning preset. ASTM C29 is a test method, not a prescribed DG density.
Product, traffic, soil, and base design determine the depth and compaction method.
Engineering Mechanics of Decomposed Granite
Decomposed granite (DG) is weathered granitic material sold as a mixture of small particles and fines. Gradation varies by quarry and product, so check the size and binder information for the material you plan to install.
Unlike clean coarse crushed granite, DG includes fine particles as well as small angular grains. Moistening and compacting a suitable product can form a firmer walking surface. Drainage, erosion resistance, and installation steps depend on the DG gradation, stabilizer, base, and site slope.
Target Compacted Volume (yd³) = [Area (sq ft) × Finished Depth (in)] / 324Estimated Loose Order (yd³) = Finished Volume × (1 + Extra Material % ÷ 100)Estimated Short Tons = Loose Order (yd³) × Entered Loose Density (short t/yd³)The calculator starts at 1.25 short tons per loose cubic yard, or 2,500 lb/yd³. It is a planning estimate, not a value set by ASTM C29/C29M. That standard describes how to measure aggregate bulk density. Published seller figures show why the density is editable: Gravelshop lists one ½-inch-minus DG at 2,410 lb/yd³, while Central Texas Materials lists its DG at 2,700 lb/yd³. Ask your supplier for the loose conversion and product-specific installation guidance before ordering.
Need a different starting point? Use the DG tons calculator when the supplier quotes by weight, or the DG coverage calculator when you already know how many tons or yards are available. These tools use the same editable loose-density and order-allowance assumptions.
Planning a DG Pathway Installation
Use the installation sheet for the exact product you buy. For example, Kafka Granite's standard pathway specification defines its own subbase, placement, and compaction requirements. Those details are product and project specifications, not defaults built into this quantity calculator.
- Set the finished grade: Mark the path edges and finished elevation, then excavate enough for the DG layer and any base your site requires. Keep the surface graded so water does not collect against a building.
- Check the subgrade: Firm up soft or wet spots before placing material. Use a separation fabric only when the soil and base design call for one; follow the fabric maker's overlap and anchoring directions.
- Place manageable lifts: Spread the DG at the thickness recommended for your product and compactor. Some stabilized blends have their own mixing and moisture instructions.
- Compact as specified: Follow the product and equipment guidance for moisture, passes, and finished thickness. Check the grade after compacting rather than assuming a fixed percentage of volume loss.
- Finish and remeasure: Add material to low areas, compact again as needed, and measure the finished layer at several points. Keep loose DG from spilling into drains or planting beds.
Frequently Asked Questions About Decomposed Granite
How much decomposed granite do I need for a 10x20 foot patio?
A 10x20 foot patio is 200 square feet. At a 3-inch finished depth, the geometric volume is 1.85 cubic yards. With the calculator’s editable 20% order allowance, plan for 2.22 loose cubic yards. At the editable 1.25-short-ton-per-yard planning density, that is about 2.78 short tons. Confirm the density and allowance for the DG you buy.
What is the difference between standard DG and stabilized DG?
Standard DG contains granite particles and fines that can be compacted for a walking surface. Stabilized products add a binder; their mixing, base, moisture, and compaction directions vary by manufacturer. A stabilizer can improve surface cohesion, but drainage and slope still need to be designed for the site.
How deep should decomposed granite be installed for pathways?
Specify the finished DG depth using the product guide and the path’s traffic, soil, and drainage conditions. The depth entered here is the finished DG layer only; it does not include a separate aggregate base. Do not apply one path or driveway section to every site.
Can decomposed granite be installed without a plate compactor?
Follow the directions for the DG product and project scale. A manufacturer may specify a plate compactor or roller for a new path, while a hand tamper may be suitable for a small repair. Walking over loose material is not a reliable compaction method; check the finished thickness and grade after compacting.