The Complete Guide to Synthetic Turf Base Prep: M10, 89, and When to Use Each
Why Proper Base Prep Is Everything
A flawless turf installation starts long before you roll out your first piece of synthetic grass. The base layer—the compacted foundation beneath your turf—determines the surface’s drainage, stability, and longevity. Skip this step or choose the wrong material, and even the most premium turf (like Turf Haus featuring NatureFlow™ backing) can develop ripples, soft spots, or poor drainage.
For professional landscapers and hardscapers, understanding how to build a correct M10 or 89 Crush & Run base is critical for ensuring top-tier performance and client satisfaction.
Understanding Turf Base Materials
Before choosing which material to use, let’s break down the two most common base types used in synthetic turf installation:
M10 – “Crush and Run” Granite Fines
Composition: Crushed granite dust and small particles that compact tightly.
Drainage: Excellent water permeability when properly compacted, yet fine enough to create a smooth surface.
Best For:
Putting greens
Residential lawns
Areas needing a level, polished finish
Depth Recommendation: 2–4 inches compacted
Rule of Thumb: ~8 tons of M10 covers 1,000 sq. ft. at 2" depth.
Because of its dense particle structure, M10 granite fines create a smooth, firm base that’s ideal under putting surfaces and high-traffic lawn areas. It provides a solid foundation that won’t shift or rut over time.
89 Stone – 3/8” Crushed Gravel
Composition: Angular 3/8” gravel pieces that interlock for strength while allowing high drainage.
Drainage: Superior permeability; water passes through rapidly.
Best For:
Heavier installations (like sports fields or commercial turf)
Poorly draining soils
Layered base systems (with M10 on top for smoothness)
Depth Recommendation: Use 2–3” of 89 Stone as a sub-base under a 1–2” M10 top layer.
Using 89 Crush and Run below M10 provides structural depth and enhanced drainage. This dual-layer method helps prevent standing water, heaving, or base failure in freeze-thaw conditions.
When to Use M10 vs. 89 Stone
| Project Type | Soil Condition | Recommended Base | Why It Works |
|---|---|---|---|
| Residential Lawn | Moderate to well-draining soil | 2–3” M10 | Smooth finish, easy to compact |
| Putting Green | Flat or gentle slope | 3–4” M10 | Tight finish ideal for ball roll |
| Large Landscape / Play Area | Mixed or heavy clay soils | 2” 89 + 2” M10 | Drainage + surface smoothness |
| Rooftop / Patio Turf | Solid substrate (concrete, wood) | Drain mat or shock pad | Lightweight & non-permeable base alternative |
| Sports Field / High Traffic | Poor drainage or heavy use | 3” 89 + 2” M10 | Maximum stability and drainage |
Proper Base Prep Process (Step-by-Step)
1. Excavate and Grade
Remove 3–4 inches of soil (or more if replacing sod). Shape the subgrade to promote natural drainage, sloping away from structures.
2. Lay and Compact Base Material
Spread M10 (or your chosen blend) evenly over the area.
Compact with a plate compactor or roller until you achieve a firm, level surface with no movement underfoot.
For dual-layer systems, compact the 89 Stone first, then cap with M10 and re-compact.
3. Check for Level and Smoothness
Use a straightedge or screed to ensure uniform elevation. Any dips will be visible after turf installation.
4. Apply Weed Barrier (Optional)
For lawns or areas prone to vegetation, we recommend installing a permeable weed barrier fabric before laying turf.
5. Lay Turf and Seam
Roll out turf and trim off the selvedge line (the factory edge). Align grain direction, secure seams with turf tape and adhesive, and anchor with turf nails or staples as needed.
6. Infill and Brush
Add infill (like Wonderfill sand - see our article on Wonderfill Sand options) evenly across the surface, typically 1” deep, to stabilize blades and promote drainage.
Drainage: The Key to Longevity
Even with the best base material, poor drainage can ruin an installation. That’s where NatureFlow™ backing makes a major difference—it’s 100% permeable, draining up to 1,000 inches per hour, compared to 40–50 inches for traditional polyurethane-backed turf. This means water moves freely through both the turf and the base, preventing mold, odor, or surface bubbling.
Quick Tips for Pro Installers
Always cut turf from the backing side to protect the blades.
For fringe and putting greens, align grain direction across all pieces.
Compact in layers—don’t dump all your base at once.
Avoid limestone or other materials that can compact too tightly and trap moisture.
Reference the Synthetic Turf Council’s official installation standards for consistency across job sites.
A well-built base is the foundation of every great turf installation. Whether you’re a seasoned landscape contractor or a designer specifying turf systems, knowing when to use M10, 89, or a combination of both ensures performance, appearance, and longevity.
With Turf Haus’s NatureFlow™ Technology, your perfectly prepped base gets paired with the industry’s most advanced turf system—lightweight, fully permeable, and 100% recyclable. Together, they create a turf installation built to perform beautifully for years to come.
