Choosing the right base material is the key to a lawn's lifespan of up to 15 years. Thoroughly compare the advantages and disadvantages of core foundation aggregates such as crushed stone and granite fines
The question what do you put under artificial turf is the most critical yet often overlooked step in a successful synthetic grass installation. While the turf itself is the visible star, the sub-base beneath it is the unsung hero that dictates the lawn’s durability, drainage, flatness, and overall lifespan—up to 15 years for a properly built foundation, versus just a few years for a poorly prepared one. Selecting the right artificial turf sub base material, from crushed stone to decomposed granite, and mastering compaction, depth, and drainage is non-negotiable for both residential and commercial installations. Whether you’re a DIY enthusiast tackling a backyard project or a professional installer designing a commercial landscape, this guide breaks down why the foundation makes or breaks your artificial lawn, compares the top core aggregates for every use case, addresses pet-specific base needs, and teaches you how to calculate compaction density and drainage for a flawless, long-lasting base. Turflory’s landscape turf experts share industry-best practices for turf foundation preparation, ensuring your synthetic grass stands the test of time, foot traffic, and the elements.
Why does the foundation material determine the success or failure of the lawn?
Artificial turf is only as good as the base it’s laid on—turf foundation preparation is the foundation of a functional, durable synthetic lawn, and the wrong material or poor installation leads to a litany of problems that ruin the turf’s performance and appearance. A well-designed sub-base does far more than just provide a flat surface: it distributes weight evenly, prevents soil erosion and settling, ensures proper drainage to avoid water pooling and mold, and creates a stable base that resists wear from foot traffic, pets, and heavy use. Conversely, a cheap or improperly prepared base (e.g., using uncompacted soil, the wrong gravel type, or skimping on depth) leads to uneven turf, ruts, waterlogging, weed growth, and even turf tearing—all issues that shorten the lawn’s lifespan and require costly repairs or full replacement.
Here’s how the right artificial turf sub base material directly impacts every critical aspect of your synthetic lawn, and why cutting corners here is never worth it:
1. Durability and anti-settling: A compacted, high-quality aggregate base prevents the soil beneath from shifting or settling over time, which causes the turf to become uneven and develop unsightly bumps or ruts. This is especially important for high-traffic areas like playgrounds, pet yards, or commercial plazas, where constant use can quickly damage a weak base.
2. Proper drainage: The single most important function of the sub-base is to channel water away from the turf surface and into the ground or drainage system. A porous aggregate base with the right gradation allows water to percolate through quickly, eliminating pooling (a major cause of mold, mildew, and turf backing damage) and keeping the lawn dry even after heavy rain.
3. Weed and pest prevention: A thick, compacted aggregate base creates a physical barrier that blocks weeds from growing through the turf and deters burrowing pests (e.g., moles, gophers) from damaging the lawn from below—eliminating the need for chemical weed killers or pest control.
4. Turf stability: A stable base keeps the artificial turf in place, preventing shifting, wrinkling, or tearing at the seams. This is critical for DIY installations, where improper base preparation is the top cause of amateur-looking results.
5. Longevity: A professionally prepared base with the right aggregates and compaction is the reason high-quality artificial turf can last 10–15 years or more. For every dollar spent on a quality base, you save hundreds in future repairs and replacement costs—making it the most cost-effective investment in your turf installation.
For Turflory’s premium landscape and pet turf products, a proper sub-base is not just a recommendation—it’s a requirement to unlock the full lifespan and performance of your synthetic grass. Turflory’s solution guides include detailed base preparation instructions tailored to every turf type, ensuring your installation is set up for success from the ground up.
Core Aggregate Selection Guide
Choosing the right aggregate is the heart of turf foundation preparation—not all gravel or stone is created equal, and the best artificial turf sub base material depends on your climate, soil type, intended use (residential, pet, commercial), and DIY skill level. The two most widely used and industry-recommended aggregates for artificial turf bases are Class II Road Base Gravel and Decomposed Granite (DG)—each with unique advantages, disadvantages, and ideal use cases. Both are porous, compactable, and provide excellent drainage, but their texture, compaction density, and cost make them better suited for different projects. Below is a comprehensive guide to these core aggregates, including how to choose, install, and use them for a perfect synthetic turf base, plus key considerations for turf base depth and aggregate gradation.
Class II Road Base Gravel (also known as road base rock) is the gold standard for artificial turf sub base material—a blend of crushed stone, gravel, and fine sand/clay fines that compacts into a hard, stable, and porous base. It’s the most versatile aggregate for all artificial turf installations, from residential backyards to commercial sports fields, and is especially ideal for areas with heavy rain, poor native soil drainage, or high foot traffic. Turflory recommends Class II Road Base Gravel for 90% of turf projects, as it checks all the boxes for durability, drainage, and ease of installation—even for DIYers.
Key Advantages:
• Superior compaction: The mix of large stone, gravel, and fines compacts into a rock-hard, stable base that resists settling and ruts, even under heavy use.
• Excellent drainage: The porous structure allows water to flow through quickly, making it perfect for rainy climates or areas with poor native soil (e.g., clay soil that holds water).
• All-weather performance: It remains stable in extreme heat and cold, won’t turn to mud when wet, and doesn’t erode or wash away with rain.
• Versatility: Ideal for all turf types, including residential, pet, playground, and commercial hardscaping base projects.
• Weed/pest resistance: The compacted structure creates an impenetrable barrier against weeds and burrowing pests.
Key Disadvantages:
• Slightly higher cost: More expensive than basic crushed stone or decomposed granite, but worth the investment for long-term durability.
• Requires proper compaction: Needs a plate compactor (the most essential compaction tool for turf bases) to achieve the right density—hand tamping is not sufficient for large areas.
Ideal Use Cases: Rainy climates, clay soil, high-traffic areas, pet yards, commercial installations, and any project where maximum durability and drainage are priorities.
Recommended Turf Base Depth: 4–6 inches for residential projects, 6–8 inches for commercial/high-traffic areas (after soil excavation and removal of topsoil/soft earth).
Decomposed Granite (DG)—a crumbly, granular aggregate made from weathered granite rock—is a popular alternative to road base gravel for artificial turf sub base material, especially for residential projects in dry, arid climates. It compacts into a smooth, fine-grained base that’s softer underfoot than road base gravel and blends seamlessly with natural landscapes. DG is a cost-effective option for DIYers and low-traffic areas, but it has limitations in wet climates or high-use spaces that make it less versatile than Class II Road Base Gravel.
Key Advantages:
• Smooth, natural finish: Compacts into a fine, dirt-like surface that’s easy to level and creates a seamless base for turf—ideal for residential lawns and garden beds.
• Lower cost: More affordable than Class II Road Base Gravel, making it a great choice for budget DIY projects.
• Easy to handle: Lighter and easier to spread than heavy gravel, perfect for small projects or DIYers without heavy equipment.
• Good drainage (in dry climates): In arid areas with low rainfall, DG provides adequate drainage and resists settling.
Key Disadvantages:
• Poor drainage in wet climates: DG turns to mud when exposed to heavy rain or standing water, leading to settling, erosion, and waterlogging—never use in clay soil or rainy regions.
• Low compaction density: While it compacts smooth, it’s not as hard or stable as road base gravel and can develop ruts in high-traffic areas.
• Weed growth risk: Fine DG particles can allow weed seeds to take root if not topped with a weed barrier.
• Not ideal for pets: Pet urine and waste can pool in the fine grains, leading to odors and mold if drainage is poor.
Ideal Use Cases: Dry/arid climates, sandy soil, low-traffic residential areas (e.g., decorative lawns, balcony turfs), and budget DIY projects.
Recommended Turf Base Depth: 3–4 inches for low-traffic residential use (after minimal soil excavation).
Pro Tip: For a hybrid base that combines the best of both aggregates, use a 4-inch layer of Class II Road Base Gravel for the bottom (drainage layer) and a 1-inch layer of DG for the top (smooth leveling layer)—perfect for residential projects that want stability and a fine finish. This is a popular Turflory-recommended hack for DIY turf base installations.
Special foundation needs of pet owners: deodorizing base material
Pet owners have unique turf foundation preparation needs that go beyond standard durability and drainage—an artificial lawn for dogs, cats, or other pets requires a sub-base that not only channels water away but also neutralizes pet urine odors and prevents bacteria/mold growth. Standard aggregate bases (Class II Road Base, DG) provide excellent drainage, but they don’t address odor retention, a common complaint among pet owners with artificial turf. The solution is to incorporate deodorizing base material into the sub-base design—specialized aggregates and additives that absorb and neutralize pet urine, keeping the lawn fresh and odor-free for years. Turflory’s pet turf solutions include tailored base recommendations for pet yards, combining drainage, durability, and deodorization for a pet-friendly synthetic lawn that stands up to messy furry friends.
Here’s how to design a pet-friendly artificial turf base with deodorizing materials, plus the best pet turf base materials to use:
1. Start with a drainage-first base: The foundation of any pet turf base is a 4–6 inch layer of Class II Road Base Gravel (the best aggregate for pet yards) compacted to 95% density—this ensures pet urine and water drain away quickly, preventing pooling and odor buildup. Avoid DG for pet yards, as it traps moisture and odors.
2. Add a deodorizing aggregate layer: On top of the compacted road base, add a 1–2 inch layer of zeolite—a natural, porous volcanic rock that is the gold standard for pet turf base materials. Zeolite absorbs pet urine and neutralizes ammonia odors (the main cause of pet turf smells) through ion exchange, trapping odor-causing molecules and preventing them from releasing back into the air. It’s non-toxic, pet-safe, and lasts for years with no maintenance.
3. Install a heavy-duty weed barrier: Lay a permeable, non-woven weed barrier over the deodorizing zeolite layer—this prevents the zeolite from mixing with the top infill (if using) and blocks weeds, while still allowing water/urine to drain through.
4. Choose pet-friendly turf top infill (optional): For extra deodorization, pair the deodorizing base with a zeolite or coconut coir infill on top of the turf—this creates a double layer of odor protection and keeps the lawn soft for pets to play on.
Alternative Deodorizing Base Materials (for budget pet owners):
• Pumice stone: A lightweight, porous volcanic rock that provides moderate deodorization and excellent drainage—more affordable than zeolite but less effective at odor neutralization.
• Crushed limestone: A basic aggregate with mild deodorizing properties, ideal for pet owners on a tight budget (pair with a zeolite infill for better odor control).
Critical Pet Base Tip: Never use non-porous materials (e.g., concrete, asphalt) for a pet turf base—they trap pet urine and water, leading to severe odors, mold, and turf damage. Turflory’s pet turf is engineered with a high-flow drainage backing that pairs perfectly with a deodorizing aggregate base, ensuring urine and water drain away in seconds and odors are neutralized at the source.
Foundation compaction density and drainage calculation
Even with the best artificial turf sub base material, a poorly compacted base or incorrect drainage design will ruin your artificial lawn—compaction density and proper drainage are the final pieces of the turf foundation puzzle, and they require precise calculation and execution. Compaction density refers to how tightly the aggregate is packed (measured as a percentage of the aggregate’s maximum density), while drainage calculation involves matching the base’s porosity and depth to your climate’s rainfall, native soil type, and turf use. For a professional-grade base, the goal is to achieve 95% compaction density (the industry standard for artificial turf) and design a drainage system that can handle the maximum expected rainfall in your area—two metrics that are non-negotiable for a long-lasting lawn. Below is a step-by-step guide to calculating and achieving the right compaction density and drainage for your artificial turf base, including the essential compaction tools and key formulas for DIYers and professionals alike.
Achieving 95% Compaction Density: Tools and Steps
Compaction is the process of pressing aggregate particles together to eliminate air pockets and create a hard, stable base—95% compaction density means the aggregate is packed to 95% of its maximum possible density, leaving just 5% porosity for drainage (the perfect balance of stability and water flow). Achieving this density requires the right compaction tools and a layered installation method (never compact a thick layer of aggregate all at once).
Essential Compaction Tools:
• Plate compactor: The most important tool for turf foundation preparation—a gas or electric plate compactor with a 12–18 inch plate is ideal for residential projects, while a larger ride-on compactor is used for commercial installations. Hand tampers only work for small, tight spaces (e.g., around garden beds).
• Rake and leveling tool: A landscape rake for spreading aggregate evenly and a laser level or string line for ensuring a flat, consistent turf base depth.
• Moisture sprayer: A garden hose with a spray nozzle—adding a small amount of moisture to aggregate (road base or DG) before compaction improves compaction density (the fines stick together better when slightly damp).
Step-by-Step Compaction Process:
1. Excavate and level the native soil: Remove 4–8 inches of topsoil/soft earth (depending on your desired base depth) and compact the native soil to 95% density with a plate compactor—this prevents the sub-base from settling into soft soil.
2. Add aggregate in 2-inch layers: Spread the aggregate (Class II Road Base or DG) in 2-inch thick layers—never add more than 2 inches at a time, as thick layers cannot be compacted to 95% density.
3. Moisten and compact each layer: Lightly spray the 2-inch aggregate layer with water (just enough to dampen the fines, not soak the stone) and run the plate compactor over it 3–4 times in overlapping passes (50% overlap) to achieve 95% density.
4. Level and check for flatness: After compacting each layer, use a rake and laser level to ensure the base is perfectly flat and at the correct turf base depth.
5. Add the final layer: Repeat the process until you reach the desired base depth, then compact the final layer an extra time for a smooth, hard finish.
Drainage Calculation: Matching Base to Climate and Soil
Drainage calculation for artificial turf bases is a simple formula that ensures your base can handle the maximum rainfall in your area, preventing water pooling and mold. The key metric is percolation rate—the speed at which water drains through the aggregate (measured in inches per hour). Class II Road Base Gravel has a percolation rate of 10–20 inches per hour (excellent for all climates), while DG has a rate of 5–10 inches per hour (only suitable for dry climates).
Basic Drainage Calculation for DIYers:
1. Find your area’s average maximum rainfall: Look up the 10-minute maximum rainfall (in inches) for your city/region (available from local weather services)—this is the amount of rain that falls in the heaviest 10-minute downpour.
2. Calculate required base porosity: The aggregate base’s porosity (5% for 95% compaction density) must be able to absorb and drain this rainfall in less than 10 minutes.
3. Choose the right aggregate: For areas with maximum rainfall over 0.5 inches in 10 minutes, use Class II Road Base Gravel (higher percolation rate). For areas with less than 0.5 inches, DG is acceptable for low-traffic use.
Additional Drainage Tips:
• Slope the base slightly: Add a 1–2% slope to the base (1–2 inches of drop per 10 feet) toward a drain, lawn edge, or garden bed—this directs water away from the turf surface and speeds up drainage.
• Install French drains (for poor soil): If your native soil is clay (percolation rate <1 inch per hour), install a French drain at the bottom of the excavated area before adding aggregate—this channels water away from the base and into a storm drain or garden.
• Use permeable weed barriers: Always use a permeable, non-woven weed barrier (never plastic sheeting) over the compacted base—plastic blocks drainage and leads to waterlogging.
Turflory’s FAQ and solution guide includes regional drainage and compaction recommendations, tailored to your climate and soil type—ensuring your artificial turf base is designed for maximum performance in your specific area.
The answer to what do you put under artificial turf is simple: a well-prepared base of high-quality, compacted aggregate—ideally Class II Road Base Gravel for most projects—paired with proper compaction, drainage, and tailored materials for pet owners or unique climates. Turf foundation preparation is not a step to rush or cut corners on: it’s the investment that ensures your artificial lawn lasts 10–15 years, remains flat and drainable, and resists wear from foot traffic, pets, and the elements. By choosing the right artificial turf sub base material, mastering compaction tools and 95% compaction density, and calculating drainage for your climate, you’ll create a foundation that makes your synthetic grass look and perform like a professional installation—whether you’re a DIYer or a seasoned contractor.
Turflory’s landscape turf and custom solutions are engineered to pair perfectly with industry-standard aggregate bases, with detailed installation and foundation guides for every turf type—from residential lawns to pet yards and commercial hardscaping. With the right foundation, your artificial turf will not only look lush and natural for years but also deliver the low-maintenance, hassle-free performance that makes synthetic grass the ultimate landscaping choice.
Forget the old adage—when it comes to artificial turf, it’s all about the base.
