Typical applications
KoirMat™ woven coir fabrics are used in erosion control and revegetation projects, including:
- Highway and railway embankments
- Slopes, channels, streambanks and riverbanks
- Wetland construction and tidal marsh restoration
- Construction sites, mining operations and landfills
- Detention ponds, dams and reservoirs
- Golf courses, ski slopes and high-altitude planting
Select the fabric grade and anchoring layout for the site conditions and project design.
Installation guidelines
These general guidelines apply to KoirMat™ 400, 700, 900 and 1000. Follow the project drawings and site-specific anchoring requirements.
Site preparation
Grade and shape the installation area. Where applicable, loosen the top 2–3 inches of soil to prepare the seedbed. Apply lime and fertilizer as specified for the site. Remove clods, rocks, wood and other obstructions so the fabric can lie in direct contact with the soil.
Seeding
Seeding may take place before installation; for open-weave matting, it may also be done afterward. Follow the project’s planting requirements. A light veneer of soil may be raked over the seeded surface, and straw or hay mulch may be added where specified. Reseed check slots and other areas disturbed during installation.
Anchoring
The existing installation guidance specifies U-shaped metal staples (11-gauge minimum, 6–12 inches long) or wooden stakes at least 12 inches long. Keep the center of the anchor at least 2 inches from the fabric edge. Choose anchor type, length and spacing for soil conditions and the project design.
See the Installation on Slopes and Installation in Channels tabs for the corresponding layout and drawings.
Installation on slopes
Complete the site preparation, seeding and anchor selection described in the Installation Guidelines tab before following this sequence.
- Prepare the site as described in the Installation Guidelines tab.
- Begin at the top of the slope and anchor blankets in a 12” deep and 12” wide initial anchor trench (see Fig.2) and anchor with staples at 18” spacing.
- Unroll blanket down slope in the direction of the water flow (see Fig.1). The blanket should not be stretched but should have full contact with the soil. Anchor blanket using staples or stakes. See “Staple Pattern Guide for Slopes” below.
- Overlap edges of adjacent parallel rolls by approximately 6” and anchor with staples at 24” to 36” spacing depending on the slope.
- When blankets have to be spliced, place upper blanket end over lower blanket end (shingle style) with 12” overlap and anchor with two staggered rows of staples at 12” spacing.
- Anchor, fill and compact ends of blankets in 12” deep and 6” wide terminal anchor trench. Anchor with staples at 18” spacing.
Staple Pattern Guide for Slopes
Figure 1
Figure 2
Figure 3
Figure 4
Installation in channels
Complete the site preparation, seeding and anchor selection described in the Installation Guidelines tab. Follow the project design for channel flow conditions and anchoring.
- Prepare the site as described in the Installation Guidelines tab.
- Dig a 12” x 12” initial anchor trench at the upstream end (see Fig.4). If there is concentrated flow at channel entrance, it is recommended that the initial anchor trench be made at least 12” upstream from the pipe opening. It is also recommended to adopt measures to reduce the velocity of flow at pipe opening.
- Dig intermittent check slots (6” deep and 6” wide) across the channel at 25’ to 50’ intervals depending on the slope gradient of the channel (see Fig.5).
- Dig 6” deep and 6” wide longitudinal trenches at the top of side slopes to anchor the blanket edges (see Fig.6).
- Dig 12” deep and 12” wide terminal anchor trench at downstream end (see Fig.7).
- Install the first blanket in the initial anchor trench, upstream, in the center of the channel and anchor with two staggered rows of staples at 6” spacing, backfill and compact.
- Do not stretch but make sure there is full contact between blanket and soil.
- In the same manner, position adjacent blankets in the initial anchor trench overlapping the preceding blanket a minimum of 8” and anchor.
- Unroll center strip downstream.
- Unroll adjacent mats downstream in a similar fashion, maintaining an 8” wide overlap. Anchor the overlapped area with staples at 16” to 18” spacing depending upon the flow velocity.
- For anchoring the middle of the blankets see “Staple Pattern Guide for Channels” below.
- Secure the edges of the blankets along the longitudinal trenches on the top of slopes with staples at 12” centers (see Fig.6).
- Fold and secure the matting snugly into all transverse check slots. Lay the matting in the bottom of the slot and then fold back against itself. Anchor through both layers of blanket at 6” intervals then backfill and compact soil (see Fig.5).
- For noncritical installations, place two staggered rows of staples at 6” spacing in lieu of check slots.
- When blankets need to be spliced, place upstream blanket over the downstream blanket with an overlap of at least 12”. Use two staggered rows of staples at 6” spacing.
- Anchor, fill and compact downstream end matting in terminal anchor trench (see Fig.7).
Staple Pattern Guide for Channels
Figure 1 Staple Pattern Guide For Channels
Figure 2 Staple Pattern Guide For Channels
Figure 3 Installation on channels
Figure 4 Initial anchor trench for channels
Figure 5 Intermittent check slot
Figure 6 Longitudinal anchor trench
Figure 7 Terminal anchor trench for slopes and channel
Technical specifications
Compare the published physical properties of the four KoirMat™ grades below. All four use woven coconut fiber. Values are taken from Nedia’s product specification sheets.
KoirMat™ grade comparison
| Property |
400 |
700 |
900 |
1000 |
| Mass per unit area (oz/yd²) |
11.8 |
20.6 |
26.5 |
30 |
| Open area (%) |
65 |
50 |
39 |
36 |
| Thickness (in.) |
0.35 |
0.35 |
0.35 |
0.35 |
| Dry tensile strength, MD × CD (lb/ft) |
504 × 480 |
1512 × 1032 |
1968 × 1416 |
2151 × 1545 |
| Wet tensile strength, MD × CD (lb/ft) |
456 × 360 |
924 × 684 |
1260 × 768 |
1810 × 1021 |
| Water absorption (% of dry weight) |
163 |
146 |
132 |
137 |
MD = machine direction; CD = cross direction. Mass: ASTM D5261. Tensile strength: ASTM D4595. Water absorption: ASTM D1117.
Expected service life
The current expected service life is 2–5 years, depending on application and exposure. The downloadable sheets still show an older longevity range; use the current range stated here and confirm project requirements with Nedia.
Download specification sheets
Confirm roll sizes, availability and project-specific performance requirements before ordering. Product selection should follow the project design, rather than fabric weight alone.
