Installing a durable paver surface, whether for a patio or a walkway, requires thorough foundation preparation. The longevity and stability of the entire structure depend on the quality of the base beneath the visible surface. If the underlying soil is improperly addressed, the pavers will inevitably shift, settle unevenly, and create trip hazards over time. Therefore, the preparation phase, starting with the complete removal of existing grass and organic material, is crucial for the project’s long-term success.
Defining the Paver Area and Depth
Before any excavation begins, the proposed paver area must be precisely marked to guide the removal process and ensure accurate material ordering. This is typically achieved by driving wooden stakes into the ground at the corners and stretching string lines taut between them to establish the exact perimeter. For irregular shapes, marking the boundary directly onto the grass using brightly colored spray paint provides a clear visual guide for the upcoming turf removal.
Determining the necessary excavation depth requires a simple calculation based on the thickness of the planned materials. The total depth is the sum of the paver’s thickness, plus the one-inch layer of bedding sand, and the four to six inches required for the compacted aggregate base. For example, a two-inch paver requires a total excavation depth of seven to nine inches. Additionally, the entire area must be planned with a slight downward grade for proper water runoff, generally sloping away from any structures at a rate of one-quarter inch per foot.
Effective Techniques for Turf Removal
The initial step in site preparation is the complete removal of the existing turf layer, which is composed of living grass, roots, and organic topsoil. Leaving this biologically active material underneath the paver base will lead to decomposition over time, creating voids and causing the finished surface to sink unevenly. The most straightforward method for small areas involves manual removal using a flat-bladed spade or a square-point shovel.
When using manual methods, the goal is to slice horizontally beneath the sod just below the dense root layer, typically about two inches deep, to separate the turf from the subsoil. This technique allows the grass to be cut into manageable strips, usually about one foot wide, which can then be rolled or folded up for easier handling. While labor-intensive, this approach offers precise control over the depth of removal, minimizing unnecessary digging in confined spaces.
For larger projects, renting a mechanical sod cutter significantly increases efficiency and reduces physical strain. This motorized machine uses a sharp, rapidly vibrating blade to cut clean, uniform strips of turf at a consistent depth, typically one to two inches. Mechanical removal is faster than manual methods, making it the preferred choice for areas exceeding 200 square feet. The removed sod should be immediately disposed of or relocated to prevent reintroducing unwanted seeds or pests into the prepared subgrade. The dense soil and root mass can be composted, used to fill low areas, or disposed of through local yard waste programs.
An alternative, passive approach for turf removal is solarization, used if the project timeline allows for several weeks of preparation. This method involves cutting the grass short and covering the area with heavy-gauge clear plastic sheeting, secured tightly at the edges. The plastic traps solar radiation, raising the soil temperature high enough to kill the underlying grass and weed seeds over four to six weeks. The resulting dead organic matter is easier to scrape away, but still requires physical removal to prevent future settlement. This method avoids herbicides and ensures a stable, non-organic foundation for the subsequent base layers.
Preparing the Subgrade for Base Material
Once the turf has been entirely removed, the exposed soil, known as the subgrade, must be prepared to receive the aggregate base material. This involves excavating the remaining soil until the calculated total depth is reached across the entire area, maintaining the pre-determined drainage slope. Any large rocks, construction debris, or residual tree roots encountered must be completely removed, as these items can cause localized settling if left in place.
The next step is the compaction of the subgrade itself, which profoundly affects the long-term stability of the paver installation. Compacting the underlying natural soil prevents it from settling further under the weight of the paver system and subsequent use. A vibrating plate compactor should be passed over the entire exposed subgrade multiple times until the soil is firm and no longer leaves deep indentations. This action increases the soil’s density, forcing out air pockets and minimizing the potential for future displacement caused by water saturation and freeze-thaw cycles. If the subgrade is excessively dry, a light misting of water can aid in achieving optimal compaction, but excessively wet subgrade must be allowed to dry first.
Following subgrade compaction, a layer of geotextile fabric is typically installed directly over the soil before the aggregate base is added. This specialized fabric serves two functions: separation and reinforcement. Separation prevents finer subgrade soil from migrating upward and contaminating the coarse aggregate base, maintaining load-bearing strength. Reinforcement distributes the applied load over a wider area, reducing localized stress and minimizing rutting or settlement. The fabric should be laid out smoothly, overlapping seams by at least 12 inches, and secured with landscape staples before the crushed stone aggregate base is placed.