Erosion Control Blanket Calculator

About the Erosion Control Blanket Calculator

Erosion control blankets (ECBs) protect bare soil on slopes, channels, and disturbed sites while vegetation establishes. Made from straw, coconut fiber, or synthetic materials, these blankets reduce rainfall impact and hold soil in place until grass roots anchor the surface.

This calculator estimates the number of ECB rolls needed based on your slope area. Standard rolls are 8 ft wide by 112.5 ft long, covering 100 square yards (900 sq ft). Some rolls are 4 ft wide for narrow applications. Overlap requirements (6‒12 inches on seams) add 10–15% to material needs.

Whether you're stabilizing a construction site, revegetating a road cut, or protecting a newly seeded slope, This calculator ensures you order enough blanket material for complete coverage.

When This Page Helps

ECB rolls come in specific sizes and need overlap at seams. Under-ordering leaves bare soil exposed to erosion, while over-ordering wastes material. This calculator accounts for the actual slope area and overlap requirements.

How to Use the Inputs

1. Measure the slope area in square feet or square yards.
2. Select the roll size (standard 100 SY or narrow 50 SY).
3. Add 10–15% for seam overlaps.
4. Review the number of rolls needed.
5. Calculate staple requirements (1–2 per SY).
6. Order materials and schedule installation before rain events.

Example Calculation

Tips & Best Practices

• Install blankets from the top of the slope downward, overlapping uphill seams.
• Use 6-inch U-shaped staples every 3–5 feet along edges and seams.
• Anchor the top edge in a 6-inch trench and backfill.
• Photodegradable blankets break down in 1–2 years as vegetation establishes.
• Seed the slope before installing blankets for best results.
• Use coconut (coir) blankets for steeper slopes — they last longer than straw.

Types of Erosion Control Blankets

Straw blankets are the most affordable and work for gentle slopes. Coconut fiber blankets handle steeper grades and last longer. Excelsior (wood fiber) blankets are biodegradable mid-range options. Permanent turf reinforcement mats (TRMs) are for channels and severe erosion sites.

Installation Best Practices

Always unroll blankets from top to bottom, parallel to the slope direction for channel linings and perpendicular for open slopes. Overlap edges 6‒12 inches. Shingle overlaps so the uphill blanket overlaps onto the downhill blanket to prevent water intrusion.

Slope Area vs. Plan Area

When measuring slopes, the actual surface area is greater than the plan (map) view area. For moderate slopes (3:1), the difference is about 5%. For steeper slopes (2:1), the surface area is 12% greater. Measure along the slope face for accurate coverage.

Regulatory Requirements

Construction sites disturbing more than 1 acre require an erosion and sediment control plan under the Clean Water Act. ECBs are a standard best management practice (BMP) accepted by all state NPDES programs.

Frequently Asked Questions

• What type of erosion blanket should I use?

  Straw blankets (Type S) work for slopes up to 3:1. Coconut/straw blends handle 2:1 slopes. Coconut fiber (coir) blankets handle steeper slopes and channels. Turf reinforcement mats (TRMs) are permanent synthetic solutions for severe erosion.

• How long do erosion blankets last?

  Straw blankets decompose in 6–12 months. Straw/coconut blends last 1–2 years. Coconut fiber blankets last 2–5 years. Synthetic TRMs are permanent. Choose based on how long your vegetation needs to establish.

• How many staples per roll?

  Plan for 1–2 staples per square yard of blanket. A 100 SY roll needs 100–200 staples. Place staples every 1 ft along edges, every 3–5 ft in the field, and every 6 inches along overlaps and check slots.

• Can I install erosion blankets on existing vegetation?

  ECBs are typically installed on bare soil that has been seeded. On slopes with partial vegetation, blankets can be installed over thin areas to help fill in. Mow existing vegetation short before installation.

• Do I need to seed before or after installing blankets?

  Seed before installing the blanket. The blanket holds the seed in place, maintains moisture, and protects seedlings. This is the standard practice for seeded slopes on construction sites and road projects.

• How much do erosion control blankets cost?

  Straw ECBs cost $0.10–$0.30 per sq ft ($25–$75 per 100 SY roll). Coconut blankets cost $0.20–$0.50 per sq ft. TRMs cost $0.50–$2.00 per sq ft. Staples add $0.03–$0.05 each.