Geofabric pins are U-shaped metal or biodegradable fasteners that hold geotextile, erosion control matting, and weed mat flat against the ground.

Without pins, any geofabric material will lift in wind, shift on slopes, and fail to do its job. The fabric itself is only half the installation. Pinning it down properly is the other half.

This article covers what geofabric pins are, which sizes suit different soil types, and how to install them correctly. All Stake Supply stocks steel fastening pins and biodegradable options for every application.

What Are Geofabric Pins

Geofabric pins (also called retaining pins, ground staples, or U-pins) are fasteners designed to anchor geotextile fabric, erosion control blankets, jute matting, coir logs, weed mat, and turf reinforcement mesh to the soil surface.

They are shaped like a U or staple. You push or hammer them through the fabric and into the ground, where the two prongs grip the soil and the crossbar holds the fabric flat.

• Material: Galvanised steel (permanent) or biodegradable composite (temporary projects)
• Shape: U-shaped with sharpened points for easier ground penetration
• Sizes: 100mm to 300mm long, with crossbar widths from 30mm to 75mm
• Applications: Erosion control, weed suppression, drainage separation, revegetation, landscaping

Every roll of geotextile, jute matting, or erosion blanket needs pins to stay in place. Without them, the material lifts at the edges, creates channels for water to flow underneath, and defeats the purpose of laying it.

Steel Geofabric Pins vs Biodegradable Pins

Steel pins and biodegradable pins serve the same function but suit different project types. The right choice depends on whether the fabric is permanent or temporary.

Steel fastening pins are the standard choice for any permanent installation. They stay in the ground as long as the fabric does.

For revegetation and temporary erosion control, biodegradable BioPins are a better option. They hold jute and coir matting in place while vegetation establishes, then break down naturally without leaving steel in the soil.

Which Size Geofabric Pin Do You Need

Pin length depends on your soil type and how much the fabric will be stressed by wind, water flow, or foot traffic. Firmer soils need shorter pins. Loose or sandy soils need longer ones.

The crossbar width matters too. A wider crossbar (75mm) spreads the holding force across more fabric, which helps on loosely woven materials like jute mesh. A narrower crossbar (30mm) is fine for tightly woven weed mat and geotextile.

If you are not sure which size you need, go one size longer than you think. A pin that is too short pulls out under load. A pin that is slightly too long just sits deeper.

How to Install Geofabric Pins Correctly

Proper pin placement makes the difference between fabric that stays put for years and fabric that lifts after the first storm. The process is straightforward, but the spacing and edge treatment matter.

1. Prepare the ground: Clear rocks, sticks, and debris that could puncture the fabric or prevent pins from seating flush
2. Roll out the fabric: Lay it flat with 100-150mm overlap at seams. Do not stretch it tight, as thermal expansion will pull pins loose
3. Pin the edges first: Start with pins along the uphill edge (on slopes) or the windward edge (on flat ground), spaced every 500mm
4. Pin the seams: Where two sheets overlap, pin through both layers every 300-500mm to prevent separation
5. Pin the field: Add pins across the interior of each sheet at 1-2m spacing, depending on wind exposure and slope angle
6. Hammer flush: Drive each pin until the crossbar sits flat against the fabric surface. A raised crossbar catches feet and equipment

On slopes steeper than 1:3 (about 18 degrees), increase your pinning density to every 500mm across the whole sheet, not just the edges. Water flowing over the fabric creates uplift force that standard spacing cannot resist.

• Pin edges and seams first, interior last
• 500mm spacing on edges, 1-2m in the field
• Increase density on slopes, windy areas, and waterways
• Always pin through overlaps at seams

How Many Geofabric Pins Per Square Metre

The number of pins you need depends on the terrain and how exposed the site is. Flat sheltered ground needs fewer pins than a windy hillside or a drainage swale.

For a typical 50m² weed mat job on flat ground, you would need roughly 75-100 pins. The 500-pack of 150mm steel pins covers most residential and small commercial jobs with plenty of spares.

For larger erosion control projects, work out the total area, multiply by 3-4 pins per m², and add 10% for waste and seam overlaps. Running short mid-job is worse than having a box left over.

Common Geofabric Pin Mistakes

Most pinning failures come from shortcuts during installation, not from the pins themselves. These are the mistakes that lead to callbacks and rework.

• Pins too short for the soil: Sandy or freshly filled ground needs 200-300mm pins. A 150mm pin in loose soil pulls out with the first heavy rain
• Too few pins on edges: The edges are where wind gets under the fabric. Skimping on edge pins saves 20 minutes and costs you a full re-lay
• No pins at seam overlaps: Unpinned seams open up and let water, weeds, and sediment through. Pin both layers together every 300-500mm
• Crossbar not flush: Pins sticking up catch mower blades, trip hazards on paths, and snag on equipment. Hammer them flat
• Using the wrong pin type: Steel pins in a revegetation project create litter once the jute breaks down. Use BioPins instead

Getting the pin selection and spacing right at the start prevents every one of these issues. If you are unsure what you need for a specific job, contact the team at All Stake Supply with your site details.

Where to Buy Geofabric Pins in Australia

All Stake Supply stocks the full range of steel fastening pins and biodegradable BioPins from their St Marys NSW warehouse.

Every order ships complete. You will not get half your pins this week and the rest next month. That complete delivery guarantee is why landscapers, councils, and civil contractors across Australia order from All Stake Supply.

• Steel fastening pins in 150mm, 170mm, 200mm, and 300mm
• Biodegradable BioPins in 100mm (1,000-pack)
• BioPin applicator gun for high-volume revegetation work
• Browse the full erosion control range for geotextile, jute matting, coir products, and more

Contact All Stake Supply for trade pricing and bulk orders, or browse the full range online.