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Silt Fence Fabric: Geotextile, GSM, and How to Choose
Silt Fence Fabric: Geotextile, GSM, and How to Choose
What silt fence fabric is, how GSM works, and how to pick the right geotextile
In This Guide
Silt fence fabric is the woven geotextile that does the actual filtering in a silt fence. Made from woven polypropylene yarns, it is permeable enough to let water seep through while the tight weave holds back suspended soil. Fabric weight, measured in GSM (grams per square meter), is the simplest way to compare how heavy-duty and durable a given silt fence fabric is.
Quick answer: Silt fence fabric is woven polypropylene geotextile that filters sediment from runoff. Higher GSM means a denser, stronger fabric that filters more and lasts longer.
What is silt fence fabric?
Silt fence fabric, also called silt fabric or geotextile silt fence, is engineered woven cloth designed for sediment control. The weave is deliberately permeable: water passes through slowly, and the openings are small enough to trap fine soil. Because it is a geotextile, it resists rot and holds up to sun and weather far better than natural materials, which is what lets it stand on a site for the duration of a project.
Understanding GSM (fabric weight)
GSM stands for grams per square meter. A higher GSM means a denser, stronger fabric that filters more sediment and lasts longer under exposure.
| Fabric weight | Duty level | Best for |
|---|---|---|
| 50 GSM | Light duty | Short-term jobs and lower sediment loads |
| 70 GSM | Standard duty | The all-purpose choice, balancing strength, filtration, and cost |
| 100 GSM | Heavy duty | Demanding sites, longer exposure, and DOT-grade work |
Rule of thumb: 70 GSM handles the majority of installations. Step up to 100 GSM when the fence has to stay in place for an extended period or when you expect heavy runoff. The 70 GSM and 100 GSM grades are NTPEP-certified and meet AASHTO/DOT standards.
Why geotextile fabric works
The geotextile weave balances two competing needs: flow rate and filtration. Open enough, and water passes without ponding excessively behind the fence. Tight enough, and fine sediment cannot slip through. Woven polypropylene hits that balance and adds the tensile strength to resist tearing when sediment loads build up against it.
Fabric only for silt fence plows
On large projects covering thousands of feet, contractors often install bulk geotextile mechanically with a silt fence plow rather than placing pre-staked fence by hand. Fabric-only rolls are made for exactly this, supplied on a 2-4 inch core in 50, 70, and 100 GSM weights. You supply the posts and the plow slices a trench and feeds the fabric in, which is far faster than hand installation across long runs.
Not sure which product fits your site? Use the Silt Fence Selector, our free interactive tool under the Resources menu, to answer a few plain-language questions and get matched to the right silt fence, height, and fabric weight for your job.
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Shop Silt FenceUse the Silt Fence SelectorFrequently Asked Questions
What is silt fence fabric made of?
Silt fence fabric is made of woven polypropylene yarns. The weave is permeable so water passes through slowly while the small openings trap suspended soil, and the polypropylene resists rot, sun, and weather.
What does GSM mean on silt fence fabric?
GSM stands for grams per square meter and measures fabric weight. Higher GSM means a denser, stronger fabric that filters more sediment and lasts longer. 50 GSM is light duty, 70 GSM is the all-purpose standard, and 100 GSM is heavy duty.
What GSM silt fence fabric should I use?
70 GSM handles most installations and balances strength, filtration, and cost. Step up to 100 GSM for demanding sites, longer exposure, or DOT-grade work, and consider 50 GSM only for short-term, low sediment jobs.
What is fabric-only silt fence used for?
Fabric-only silt fence is bulk geotextile on a roll, installed mechanically with a silt fence plow on large projects covering thousands of feet. It is faster than placing pre-staked fence by hand over long runs.
Is silt fence fabric the same as geotextile?
Silt fence fabric is a type of woven geotextile engineered specifically for sediment control. Not all geotextiles are silt fence fabric, but silt fence fabric is always a geotextile.