You have just purchased a polypropylene geomattress to reinforce a steep slope, stabilize a permanent vegetated slope, or replace an organic biomat where the Caribbean climate degrades natural fiber prematurely. In this guide, we show you how to install it correctly: the secret is to fill the three-dimensional matrix with topsoil so that the roots interlace with the synthetic fiber.
Product specifications
The polypropylene geomattress is a three-dimensional synthetic blanket made of interwoven PP filaments that create an open, permanent matrix. Unlike a natural fiber biomat, the geomattress does not biodegrade: it remains as a definitive reinforcement for the slope and acts as a framework where roots entangle and consolidate the soil. The Dodom range is offered in a single standard configuration, sized for steep slopes, riverbanks, and permanent landscaping works.
| Specification | PP Geomattress 100 g/m² green |
|---|---|
| SKU | 654245 |
| Material | Synthetic Polypropylene (PP) |
| Structure | Three-dimensional (3D) matrix |
| Basis Weight | 100 g/m² (3 oz/yd²) |
| Color | Green |
| Roll width | 5.2 m (17 ft) |
| Roll length | 100 m (328 ft) |
| Coverage per roll | 520 m² (5597 ft²) |
| Lifespan | Permanent (non-biodegradable) |
Step-by-step instructions for use
The geomattress works as a three-dimensional framework, not as a surface cover. The difference with a biomat lies in a critical detail: the 3D cells must be filled with topsoil so that the roots interlace with the filaments. If you install it like a flat mat, it will not work. Follow the strict order.
Prepare the surface
Remove loose stones, thick roots, and plant debris. Level depressions by filling them with soil from the site and compact lightly. For geomattresses, the surface must be firm and smooth: any unevenness prevents the 3D matrix from resting uniformly.
Excavate the top anchor trench
At the crest of the slope, dig a trench 20 to 30 cm (8 to 12 in) deep and 20 cm (8 in) wide. For geomattresses, the trench must be deeper than for biomats because the anchors will bear load throughout the product's life, not just during vegetation establishment.
Add topsoil and sow the first batch
Spread a layer of 1 to 2 cm (0.4 to 0.8 in) of topsoil over the prepared ground and sow seeds directly on it. This first sowing will root within the matrix when you place the geomattress over it.
Unroll from top to bottom
Place the roll at the crest and unroll it along the slope, never parallel to it. Insert the first edge into the anchor trench. Let the geomattress fall under its own weight, without tensioning. It must make full contact with the ground and conform to gentle irregularities.
Anchor with pins and caps
Drive metal pins with anchor caps in a staggered pattern every 1 m (3.3 ft) in the body and every 50 cm (20 in) at the edges. For slopes with a gradient greater than 50%, reduce spacing to 60 cm (24 in). In the top trench, anchor densely, backfill with soil, and compact.
Overlap adjacent rolls
Overlap 15 cm (6 in) between consecutive rolls, always in the direction of water flow: the downstream roll goes under the upstream one. Reinforce the overlap line with an additional row of pins. This prevents water from entering the joint and washing away the backfill soil.
Fill the matrix with topsoil
This is the decisive step and what distinguishes a professional installation. Spread topsoil over the extended geomattress and work it with a rake or brush so that it penetrates into the 3D cells until they are full. The fiber should remain partially visible but with soil in every gap.
Second sowing and initial watering
Spread a second batch of seeds over the backfill soil, close the bottom edge in a second trench at the base of the slope, and water the entire surface with a gentle spray. This double sowing doubles the density of the final coverage.
If you have a slope exposed to full sun and strong winds, mix the backfill soil with a little coconut fiber or shredded straw. The mixture retains more moisture within the 3D matrix during the first few weeks, when the seeds have not yet germinated and the loose substrate evaporates quickly.
Do not install the geomattress without filling the 3D matrix with topsoil. If the cells are left empty, the product will not work: the synthetic fiber remains like a rug in the air, the roots do not interlace, and the first heavy rain washes away everything underneath. Filling the matrix is not optional; it's half the job.
Biomat or geomattress for your slope?
If you are wondering whether to use a coconut biomat or a synthetic geomattress, or you don't know how many pins and rolls you need for the slope you are working on, ask the virtual assistant. It will guide you based on inclination, exposure, and expected lifespan.
Complementary Products
Geomats require robust anchoring and permanent vegetation. The three complementary products listed are those that any standard installation will need, regardless of the country region where it is installed.
The 50 cm (20 in) metal rod is the standard geomat anchor: it penetrates deep enough to hold the 3D matrix even in loose soils. The anchor cap distributes the pressure on the synthetic fiber and prevents the rod from tearing the material over time. Bermuda grass seeds are the most suitable vegetation cover for Caribbean climates: aggressive, drought-resistant, and quick to cover the mat before the synthetic fiber becomes visible.
Maintenance and Care
The synthetic geomat does not degrade, so its maintenance focuses on protecting the fill soil and vegetation cover during the first few weeks:
- Intensive initial watering: For the first 2 to 3 weeks, water daily with a gentle spray. The soil within the matrix dries faster than bare ground, and germination needs constant moisture.
- Inspection after every heavy rain: Specifically check ditches, anchors, and overlaps. If you see the matrix with empty cells because water has washed away soil, refill before the problem worsens.
- No traffic for 60 days: Foot traffic compacts the soil within the matrix, sinks the fiber, and kills germination. Fence off the slope with netting or tape until you see visible cover.
- Visible fiber is not a problem: If after several months you still see the green PP through the vegetation, it is not a defect. The synthetic fiber is designed to remain and provide permanent reinforcement to the root-soil system.
- Storage of leftover rolls: Store in a dry, shaded place. Polypropylene has UV treatment, but prolonged sun exposure before installation reduces its lifespan.
Frequently Asked Questions
How long does a polypropylene geomat last on site?
The synthetic geomat is permanent: it remains on the slope as definitive reinforcement for the root-soil system. The UV-treated PP fiber maintains its mechanical capacity for several decades under normal conditions. Once the vegetation cover is established, the geomat acts as a hidden framework under the grass and does not require replacement.
Coconut biomat or synthetic geomat, how to choose?
Use coconut biomat on moderate slopes (up to 33°), landscaping projects seeking an organic solution and natural aesthetic, or when the area vegetates relatively quickly. Use synthetic geomat on steep slopes (over 33°), canal banks with permanent flow, road embankments, and any scenario requiring permanent soil reinforcement beyond the vegetation establishment period.
Up to what slope can I install the geomat?
The 100 g/m² geomat performs well on slopes up to 1V:1H (a 45° or 100% slope). Above this value, it is still valid, but the anchoring design requires specific calculations: higher rod density, reinforcement with intermediate geogrid, or subdivision of the slope into berms. For vertical or wall-like slopes, the appropriate solution is no longer a geomat but a reinforced wall with uniaxial geogrid.