Leveling a yard is often necessary for improving surface drainage, eliminating tripping hazards, or preparing a uniform base for laying sod or installing hardscaping materials. The success of this project depends on accurately determining the volume of material needed, as underestimating halts work and overestimating wastes resources. The calculation process involves measuring existing imperfections, applying a mathematical formula, and accounting for the natural settling of the material.
Measuring Yard Imperfections and Calculating Volume
The first step in determining the necessary volume of dirt involves establishing a consistent reference plane across the area to be leveled. This is accomplished by driving wooden stakes into the ground at the corners and running string lines tautly between them. Using a line level, adjust the strings until they are perfectly horizontal, creating a defined boundary for the new surface.
To find the average depth, measure the distance from the established string line down to the existing ground at multiple points within the area. These measurements, typically taken in feet, should be averaged to find the required fill depth (H). Once the length (L), width (W), and average depth (H) are known, the total volume (V) in cubic feet is found using the formula: V = L x W x H. Since bulk soil is typically sold by the cubic yard, the calculated cubic footage must be divided by 27.
For example, if an area is 10 feet long and 20 feet wide, and the average required fill depth is 4 inches (0.33 feet), the calculation is 10 ft x 20 ft x 0.33 ft = 66 cubic feet. Dividing this by 27 yields a volume of 2.44 cubic yards. This calculated volume represents the loose material before compression, but soil naturally settles when disturbed and compacted. Therefore, add a buffer of 10–15% to the total volume to account for this settling and ensure enough material is delivered to achieve the final grade.
Materials may sometimes be sold by weight in tons rather than volume in cubic yards, which introduces another conversion factor. One cubic yard of loose, dry topsoil generally weighs between 1.0 and 1.3 tons. The actual weight is highly variable, depending on the moisture content and the soil’s composition, with wet or clay-heavy material weighing significantly more. Ordering by cubic yard is generally more reliable for volume-based projects, but if ordering by ton, confirm the specific material density with the supplier to prevent miscalculation.
Choosing the Right Fill Material
Selecting the correct material is determined by the required fill depth and the intended use of the final surface. For deep depressions, typically requiring more than 4 inches of fill, fill dirt or subsoil is the most cost-effective choice. This material is primarily composed of inert mineral particles like sand, silt, and clay, lacking the organic matter found in topsoil. The absence of organic matter prevents future settling that occurs as organic material decomposes, providing necessary stability for building up the grade.
If the area requires only a shallow correction of 1 to 3 inches, or needs to support plant growth immediately, screened topsoil is the preferred option. Screened topsoil is processed through a mesh to remove large debris, resulting in a fine, uniform texture rich in organic material and nutrients. Although more expensive than fill dirt, it offers better aeration and drainage characteristics for healthy root development. If fill dirt is used to fill a deep void, it must be capped with at least 4 to 6 inches of screened topsoil to create a viable planting medium.
For minor leveling corrections on an existing lawn, a process known as top-dressing is used, which avoids disturbing the existing turf. This technique involves spreading a specialized leveling mix, often a blend of fine sand, topsoil, and compost, directly over the grass. The sand promotes drainage, while the compost supplies nutrients, allowing the grass to grow up through the thin layer without being smothered. This method is suitable only for shallow, widespread unevenness, not for filling deep holes or significantly changing the overall yard grade.
Delivery Considerations and Site Preparation
Once the material volume has been calculated and the type of material selected, attention turns to the logistics of delivery and site readiness. When placing the order, communicate the volume in cubic yards along with the specific material type, such as “screened topsoil” or “compactable fill dirt.” Arrange for the delivery truck to have clear, unobstructed access to the drop site, and mark the area clearly for the driver. Laying down large tarps where the material will be dumped helps keep the site clean and makes cleanup of residual dirt easier.
Before the material arrives, the area needs preparation to ensure the new fill properly integrates with the existing ground. Large debris, such as rocks, roots, or dead weeds, should be removed from the surface. The existing soil should be lightly loosened, perhaps with a rake or mechanical tiller, to a depth of an inch or two. This light scarification helps create a better bond between the new, loose material and the native soil, preventing slippage and subsequent erosion.
The Leveling and Compaction Process
The physical process of applying the fill material must be executed in a controlled, layered manner to guarantee long-term stability. Instead of dumping all the material in the low spots at once, the fill should be added in shallow layers, ideally no deeper than 4 to 6 inches at a time. This layered approach is necessary because loose soil must be compacted to achieve a stable density that resists future settling.
After each layer of material is spread using a shovel and a grading rake, it must be compacted. Compaction is achieved by using a plate compactor or a heavy lawn roller, which applies mechanical force to press the soil particles closer together. Compacting in thin layers ensures that the force penetrates the full depth of the new material, eliminating air pockets that would otherwise collapse over time and create new depressions. For large projects, this process aims for a specific density, often a 95% compaction rate relative to undisturbed native soil, to provide a firm foundation.
After the final layer has been spread and compacted, the original string lines should be used again to verify the final grade. A long, straight screed board can be dragged across the surface, riding on the established strings, to scrape away excess material and fill any minor low spots. This results in a perfectly level plane and ensures the entire area meets the intended specification before the final steps of seeding or sod installation begin.