Why installing over an existing lawn usually fails
Live turf and topsoil are organic, spongy, and full of fines. That layer holds moisture, collapses as it decomposes, and clogs the perforations in synthetic turf backing. Water backs up, infill gets muddy, and the surface can feel soft or uneven. Do it once, do it right. Start with a purpose-built base.
What a drainage-ready base looks like
- Excavation depth: Typically 3 to 6 inches of soil removed, adjusted for soil type, rainfall, and use.
- Slope: 1 to 2 percent away from structures or to a drain. Keep grade consistent.
- Separation fabric: Nonwoven geotextile to separate soil from base and help control weeds.
- Base rock: Clean, angular crushed stone, open graded. Avoid pea gravel and heavy fines that impede flow.
- Compaction: Mechanically compact in thin lifts until firm and stable.
- Leveling course: Thin layer of smaller angular stone to fine tune grade, lightly compacted.
- Perforated turf backing: Quality turf with consistent punch holes to let water through.
- Infill: Free-draining infill sized for your turf. For pets, use antimicrobial options that do not clump.
- Edge restraint: Secure edging or mow strip to lock the system in place.
- Drain tie-ins: Direct downspouts and surface drains away from the turf or into dedicated drainage.
Step by step: build the right base
Tools and materials
- Sod cutter or shovel, wheelbarrow
- Nonwoven geotextile fabric and landscape staples
- Crushed stone base and smaller angular topping stone
- Plate compactor, hand tamper, rake, screed board
- Edging, spikes, seam tape and adhesive
- Artificial turf, infill, stiff broom, hose
Installation steps
- Remove all sod, roots, and organic soil to the planned depth. Cap or reroute irrigation.
- Rough grade the subgrade with a consistent 1 to 2 percent slope.
- Lay geotextile fabric across the subgrade with overlaps facing downslope.
- Place the first lift of clean, angular base rock. Spread evenly.
- Compact thoroughly. Add additional lifts and compact until you reach final elevation.
- Add a thin leveling course of smaller angular stone. Screed flat, then lightly compact.
- Install edging to hold the system. Confirm final slope.
- Roll out turf, relax it in the sun, trim to fit, seam per manufacturer guidance.
- Add infill in light passes and brush it in to stand fibers up and maintain permeability.
- Hose test several spots. Water should disappear quickly without pooling.
Soil and climate considerations
- Heavy clay: Use a deeper, open-graded base. Consider French drains or channel drains at low points.
- Sandy soils: Still build a base for stability. Sand alone shifts under load.
- Freeze and thaw: Favor angular stone with minimal fines and solid compaction to limit movement.
- High rainfall: Increase base depth and provide overflow paths or tie-ins to site drainage.
Drainage checks and upkeep
Before final seaming
- Hose test the compacted base. Water should infiltrate fast without washing fines.
After installation
- Brush fibers and maintain infill levels so water can pass through the backing.
- Keep leaves and debris off the surface. Clear nearby downspouts.
- If pets use the area, rinse routinely to keep the system fresh and flowing.
Costs and timeline
Base preparation is the bulk of a quality install. Professional projects often range from $8 to $20 per square foot installed, with 40 to 60 percent tied to base work and site conditions. DIY material costs for base layers typically run $2 to $5 per square foot depending on depth and region.
Common mistakes to avoid
- Laying turf directly over sod or thatch.
- Using pea gravel or rounded rock that will not compact.
- Relying on sand or thick fines that trap water.
- Skipping geotextile separation on soft soils.
- Zero slope or grading toward structures.
- Ignoring downspouts and site drainage paths.
When a direct overlay might be acceptable
Short-term displays or temporary event areas on dry, well-drained ground can use drainage grids or panels over scalped grass. Expect reduced performance and plan to remove after the event.
Talk with FusionTurf
Want drainage you never have to second guess? Our national dealer network builds stable, permeable bases that perform. Tell us your site conditions and we will recommend the right system.
