Silt fencing is one of the most widely used erosion control measures on construction sites. While silt fencing may seem like a simple piece of black mesh strapped to wooden beams, there are close to half a dozen different types of fences, each with their unique benefits.
Choosing the wrong type for your site conditions can lead to costly compliance issues, sediment runoff, and ineffective perimeter control.
Whether you’re overseeing a residential build, roadway project, or large-scale commercial development, understanding the different types of silt fencing and their applications is key to proper stormwater management and environmental compliance. In this guide, we’ll walk through the primary types of silt fencing, when to use them, and what to consider during selection and installation.
The Importance of Silt Fencing
Silt fences are temporary sediment barriers that prevent soil erosion and keep sediment-laden runoff from a disturbed site. Typically made from woven or nonwoven geotextile fabric attached to wooden or metal posts, these fences are installed along slopes, property boundaries, and drainage pathways to slow water flow and trap sediment.
In addition to reducing off-site sediment runoff, silt fences can help you meet proper permitting requirements, such as NPDES and SWPPP.
However, to achieve those outcomes, choosing the right material and configuration for your site is critical.
Common Types of Silt Fencing
Several types of silt fence are available, and each is engineered to perform under specific site conditions. Let’s take a closer look to find out which is right for your site:
1. Standard Duty Silt Fence
Best for: Flat or gently sloped areas with minimal water flow.
Standard silt fencing is the most basic and widely used option. It typically consists of woven polypropylene fabric supported by hardwood stakes spaced 6 to 10 feet apart. These fences are intended for sheet flow control in low-velocity runoff areas and help trap fine sediment particles before they are discharged with the resulting runoff.
Key Features:
- Economical and easy to install
- Minimal tensile strength
- Lower sediment retention capacity
- Not suited for concentrated flow or steep slopes
2. Heavy-Duty Silt Fence (DOT Grade)
Best for: Roadways, highways, and large-scale commercial projects.
This grade of silt fence is built to meet Department of Transportation specifications and is significantly more robust than standard fence. It includes reinforced fabrics, stronger posts (sometimes steel T-posts), and tighter spacing for added strength and durability.
Key Features:
- High tensile strength and UV resistance
- Designed for high-volume runoff
- Longer service life and reusability
- Required for compliance with DOT and government-funded jobs
3. Wire-Backed Silt Fence
Best for: Steep slopes, high-flow areas, and extended use.
This type of fence includes a welded wire mesh backing attached to the geotextile fabric. The added support prevents blowouts, tearing, and collapse under heavy sediment loads or fast-moving water. It’s commonly used in hilly or erosion-prone areas where a standard silt fence would quickly fail.
Key Features:
- Superior strength and structural integrity
- Withstands high flow velocities
- Extended lifespan (6–12 months+)
- More labor-intensive to install
4. Super Silt Fence
Best for: Critical infrastructure, sensitive environments, and long-term control.
Super silt fence combines heavy-duty woven fabric, wire mesh, and steel posts for ultimate sediment control. Often specified in urban developments or near water bodies, this system is highly effective but comes at a higher material and installation cost.
Key Features:
- Maximum protection in sensitive or regulated areas
- Recommended for use near streams, wetlands, or stormwater inlets
- May include trenching or toe-in requirements for added stability
What to Consider When Choosing a Silt Fence
Selecting the correct type of silt fencing goes beyond just the slope and site conditions. Several other key factors can determine which option is right for your project:
- Site Slope and Flow Velocity: Steeper slopes or areas with concentrated flow require reinforced or wire-backed fencing. Standard silt fence is only appropriate for flat or gently sloped sites with sheet flow.
- Soil Type: Fine soils like silt and clay are more prone to erosion and can clog lower-grade fabrics. In these cases, a heavier-duty fence with tighter weave and greater filtering ability is recommended.
- Project Duration: If the fence will remain in place for several months or over winter, opt for higher UV-resistant fabrics and stronger posts to avoid degradation or collapse.
- Regulatory Requirements: For guidance, check local and state-level erosion control manuals or your stormwater pollution prevention plan (SWPPP). DOT projects or large commercial sites often require wire-backed or super silt fence installations for compliance.
- Maintenance Capabilities: Even the strongest silt fence will fail without proper maintenance. Consider how accessible the fence line will be for inspection, sediment removal, and repairs. Simpler designs may be more manageable for crews with limited resources.
Installation Tips: Getting It Right the First Time
Proper installation is just as important as selecting the right fence. A poorly installed silt fence will almost certainly fail, resulting in several negative consequences, including sediment runoff and compliance issues.
Best practices for installing a silt fence include:
- Trenching the bottom edge at least 6 inches into the ground to prevent undermining.
- Stapling or tying fabric securely to posts or wire mesh.
- Spacing posts 6–8 feet apart (closer for higher-grade systems).
- Turning the fence ends up slope to form a “J-hook” that helps pond water and reduce flow.
- Inspect fences after storms and remove accumulated sediment before it overtops.
Remember: A silt fence is not a dam. It’s meant to slow water, not stop it entirely. Proper layout and flow management upstream will reduce the burden on your silt fence system.
Silt Fence Alternatives and Add-Ons
While silt fencing is effective, it’s often used alongside or replaced by other erosion control products, depending on the phase of construction and site complexity.
These may include wattles, inlet protection devices, and erosion control blankets designed to prevent nearby erosion and add a second layer of sediment control.
Pairing silt fencing with the right combination of practices will give your project the best shot at staying compliant and environmentally responsible.
For more information about erosion control best practices and strategies, contact Valor Environmental for all your erosion control needs.
FAQs
How long does a silt fence last?
Depending on material and weather conditions, most silt fences are designed to last 6–12 months. Reinforced or super silt fencing can last longer if maintained properly.
Can I reuse silt fence material?
In most cases, no. Once geotextile fabric has been exposed to UV light and sediment loads, its integrity is compromised. For safety and compliance, use new material for each project.