Landscape fabric is a geosynthetic material used beneath aggregate surfaces to enhance stability and longevity. When placed under gravel, its primary function is to act as a separation layer between the native soil and the aggregate material. This barrier prevents the gravel from mixing with the underlying soil, a process known as ‘pumping’ or ‘contamination,’ which causes the surface to become muddy and unstable. The fabric also serves as a physical barrier to suppress weed growth from seeds or roots already present in the soil below.
Site Preparation and Material Selection
Site preparation is necessary to ensure a smooth, stable foundation. The designated area must be completely cleared of all existing vegetation, including grass, weeds, and deep-rooted perennial weeds, with all roots removed to prevent regrowth. After clearing, the subgrade must be raked smooth and level, ensuring proper grade or slope for water runoff and drainage away from structures. Finally, the soil should be compacted with a plate compactor or hand tamper to create a firm, stable base that minimizes future settling or shifting under the weight of the gravel.
Selecting the correct material is important, as not all landscape fabrics are suitable for use under heavy aggregate. For gravel applications, especially in areas subject to foot or vehicle traffic, a high-strength woven geotextile fabric is the recommended choice. Woven fabrics offer superior tensile strength and stabilization, providing the support needed to bear the load of the gravel and resist tearing from sharp stones. Non-woven fabrics, while highly permeable, lack the necessary durability and are prone to stretching under load, making them a less ideal option for gravel pathways or driveways.
The type and depth of the gravel aggregate should be determined based on the area’s use. For walkways and light-traffic areas, a finished depth of 2 to 3 inches is sufficient to cover the fabric. High-traffic areas, like driveways, may require a base layer of 4 to 6 inches for stability. Crushed stone, such as angular granite or limestone, is preferred for its interlocking properties, which help the gravel bind together and resist movement. Smooth materials like pea gravel are best reserved for decorative areas without heavy use.
Securely Laying the Fabric
With the ground prepared and compacted, the fabric can be rolled out, beginning at one end of the area. Unroll the material smoothly, pulling it taut to avoid wrinkles or folds that could compromise stability. If the area requires multiple sections, a generous overlap between pieces is necessary to prevent soil exposure and weed penetration at the seams. A minimum overlap of 6 to 12 inches is recommended to ensure complete coverage, accounting for any slight shifting during gravel application.
The fabric must be secured firmly to the ground before the gravel is introduced to prevent movement or bunching. Landscape staples, or U-shaped metal pins, should be driven into the ground along the perimeter to secure the edges. Staples should also be placed along all overlapped seams, spaced approximately every 8 to 12 inches to maintain a secure bond between sections. For areas with existing obstacles, such as utility pipes or trees, the fabric should be cut with a sharp utility knife using a clean ‘X’ or radial cut, then tucked around the object and secured with pins to close the gap.
Applying and Finishing the Gravel Layer
Before applying the gravel, any planned edge restraints, such as metal edging, paver borders, or timber, should be installed along the perimeter. These restraints are necessary to contain the aggregate and maintain the desired shape and depth. When introducing the gravel, exercise caution to prevent the weight of the dumping material from tearing the secured fabric or pulling out the staples. A practical technique is to dump the gravel onto a shovel or a piece of plywood placed directly on the fabric, and then manually spread the material away from the initial pile.
The gravel should be spread evenly to achieve the desired finished depth, typically between 2 and 4 inches, using the back of a metal rake. Using the flat side of the rake avoids snagging the fabric with the tines, which could cause it to pull up or tear. Ensure that the entire surface of the landscape fabric is covered, as prolonged exposure to ultraviolet light will cause the material to degrade prematurely. Once the gravel is distributed, the surface can be lightly compacted or settled with a plate compactor to enhance stability and create a uniform look.