Field Tool
Silt Fence Materials Calculator
Estimate linear footage, stakes, and overlap requirements for a silt fence run by site perimeter and slope conditions.
For planning purposes only
Estimate for planning purposes only, based on standard industry stake spacing and fabric overlap guidance. Final BMP design and material quantities must follow the approved SWPPP/plan set and be verified with your engineer of record or local jurisdiction (AHJ) before ordering or installation.
Need this installed, not just estimated? LES installs, maintains, and documents silt fence across Central Florida.
Need this installed? Request a BMP ProposalSilt Fence Quantity FAQ
How much silt fence do I need for my site?
Start with the linear footage of the disturbed perimeter you need to protect, not the total property line — silt fence is only installed where sheet flow leaves disturbed ground. Add a wastage allowance for overlap at seams, J-hooks at the ends, and tie-ins; this calculator defaults to 10%. On a rectangular one-acre pad you are usually in the 800 to 900 linear foot range, but layout follows contours rather than the lot shape, so the real number comes off the site plan.
How far apart should silt fence stakes be spaced?
Spacing tightens as slope increases, because steeper ground puts more flow and more load against the fabric. This calculator uses 8 ft on flat ground (0-5%), 7 ft on moderate slopes (5-15%), and 6 ft on steep slopes (15%+). Manufacturer requirements and site-specific BMP design take precedence over any rule of thumb.
How much overlap is needed where two rolls of silt fence meet?
Seams are where runs fail, so overlap increases with slope: roughly 6 inches on flat ground, 8 inches on moderate slopes, and 12 inches on steep slopes. Fabric should be overlapped and secured so flow cannot find the joint, and joints should not be placed at a low point where water concentrates.
How many rolls of silt fence is that?
Silt fence fabric is commonly supplied in 100 ft rolls, so the calculator divides your adjusted length by 100 and rounds up. Order in whole rolls and keep the remainder on site — repairs after a storm are far easier when spare fabric and stakes are already in the truck.
Is this estimate accurate enough to order materials?
It is a planning estimate. It reflects standard spacing and roll lengths, not your approved SWPPP, your soil conditions, or what the authority having jurisdiction requires on that project. Use it to budget and to sanity-check a quote, then confirm quantities against the approved plans before ordering.
Need BMP support on an active site?
Send us the site location, photos, plans, or SWPPP and we'll respond with scope and next steps — typically within one business day.
Need erosion control, silt fence, BMP maintenance, or post-rain inspection support? Call 407-502-6476 or request a BMP proposal from Local Environmental Services.