Why a geotextile underlay matters
A geotextile is the quiet workhorse in a high performing artificial turf system. It separates soil from your base rock, filters water so the base does not clog, and stabilizes the platform so foot traffic, pets, and play do not pump mud into the base. That means faster drainage, fewer soft spots, and longer service life.
- Separation: Keeps soil fines out of the base so voids stay open.
- Filtration: Lets water pass while retaining fines in place.
- Stabilization: Reduces rutting and settlement under load.
- Consistency: Helps maintain a smooth, even surface over time.
Where it goes in the build
Typical layer order for soil installations:
- Native soil subgrade compacted and graded.
- Non-woven geotextile placed flat and anchored.
- Free draining angular base rock compacted in lifts.
- Fine grading layer such as quarter minus compacted.
- Turf backing installed and seamed.
- Infill added and groomed.
When it is essential
- Clay, silt, or mixed soils that shed fines into the base.
- High use areas such as play zones, pet runs, or sports applications.
- Wet climates or freeze thaw regions where pumping and heaving are common.
- Any project targeting maximum drainage and durability.
When you might skip or adjust
- Over concrete or asphalt bases the fabric is not needed. Consider a drainage mat if water needs a path.
- On deep, clean, free draining sand it can be optional, though many pros still use it to stabilize the base and block fines migration over time.
- Rooftops or specialty systems should follow the specific assembly from the turf manufacturer.
What to buy for geotextile under artificial turf
- Type: Non woven needle punched, permeable, polypropylene.
- Weight: Commonly 4 to 8 oz per square yard. Heavier fabrics offer more robustness on soft clays or higher loads.
- Permeability: Designed to pass water quickly while retaining fines.
- UV and durability: Inert, rot proof, and stable in typical buried conditions.
- Not this: Woven landscape weed fabric is not a substitute for drainage and separation.
Installation steps that deliver results
- Grade and compact the subgrade. Remove organics and high spots. Aim for a smooth, firm surface with a slight positive slope away from structures.
- Place the geotextile. Roll it out flat on the soil, keep it taut, and avoid wrinkles.
- Overlap correctly. Overlap seams 6 to 12 inches. Run overlaps with the slope so water does not catch at the seam.
- Anchor the fabric. Use 6 inch sod staples, U pins, or landscape spikes every 3 to 5 feet and closer at seams and edges.
- Place angular base rock. Install in compacted lifts to the specified depth, then add a thin fine grading layer and compact to final grade.
- Install turf and infill per manufacturer guidance.
Drainage and base tips
- Use angular, free draining base rock. Avoid excessive stone dust that can trap water.
- Maintain 1 to 2 percent slope toward a drain path. Tie into French drains or catch basins if needed.
- In heavy rain or clay soils, increase base depth or include subsurface drains for peak performance.
Cost and value
Non woven geotextile typically adds about $0.10 to $0.35 per square foot depending on weight and roll size. That small cost protects the base from contamination, supports faster drainage, and reduces rework over the life of the system.
Common mistakes to avoid
- Putting fabric on top of the base instead of on the soil.
- Using woven weed barrier that blocks water or tears easily.
- Too little overlap at seams or leaving wrinkles that telegraph through.
- Letting fabric get muddy before placing base.
- Skipping edge restraint details that keep the system locked in.
Specifier notes for pros
- Call out a non woven separation geotextile between subgrade and base in drawings and specs.
- Match fabric weight to subgrade conditions and loading. Heavier on soft clays or vehicular edges.
- Detail base depth by use case, drainage strategy, and slope. Include overlap and anchoring notes.
