Whether you're building an underground drainage system, a French drain filter trench, a separation layer under decorative gravel, or need to protect a dam or reservoir geomembrane against puncture by stones, PET nonwoven geotextile is the component that separates, filters, and protects for decades without rotting. This guide explains how to choose the correct weight between 100, 200, and 400 g/m² depending on the application, how to unroll it, and how to ensure correct overlap at joints for the system to function effectively.
PET nonwoven geotextile is not a structural component—it does not provide significant tensile strength. Its function is to filter water while retaining fines, separate layers of different materials, and absorb minor puncturing forces. If your project requires structural reinforcement (MSE walls, heavy road base reinforcement), the correct choice is PET woven geotextile or geogrids, not this product. Read this entire guide before ordering quantities to confirm that nonwoven PET is the correct material for your application.
Product Specifications
Polyester (PET) nonwoven geotextile is offered in three weights, supplied in rolls 5.95 m wide by 100 m long. Each weight is calibrated for a different application scale. The table below provides the full technical specifications for the three available variants:
| Specification | 100 g/m² white | 200 g/m² black | 400 g/m² white |
|---|---|---|---|
| SKU | 764389 | 709840 | 909095 |
| Material | Virgin needle-punched PET | Virgin needle-punched PET | Virgin needle-punched PET |
| Type | Nonwoven | Nonwoven | Nonwoven |
| Weight | 100 g/m² (3 oz/yd²) | 200 g/m² (6 oz/yd²) | 400 g/m² (12 oz/yd²) |
| Color | White | Black | White |
| Roll width | 5.95 m (19.5 ft) | 5.95 m (19.5 ft) | 5.95 m (19.5 ft) |
| Roll length | 100 m (328 ft) | 100 m (328 ft) | 100 m (328 ft) |
| Area per roll | 595 m² | 595 m² | 595 m² |
| Recommended application | Professional landscaping, agricultural drainage, and light filter trenches | Standard civil engineering, road separation, and low-to-medium traffic roads | Geomembrane protection and audited hydraulic works |
| Chemical resistance | Inert to acids and typical soils | Inert to acids and typical soils | Inert to acids and typical soils |
| Estimated lifespan | Decades buried | Decades buried | Decades buried |
Installation steps are common to all three variants. Where the technique differs by weight, the step text explicitly indicates it. Before starting, confirm with your project designer that the chosen weight corresponds to the application: 100 g/m² is insufficient for geomembrane protection, and 400 g/m² is over-dimensioning for gardening.
The sister guides for PP nonwoven geotextile, PET woven geotextile, and PP woven geotextile cover the other three variants in the family: nonwoven PP is the economic alternative for gardening and agriculture, woven PET is the structural version with low creep for MSE walls, and woven PP covers road stabilization and structural weed control.
Step-by-step usage guide
The following procedure covers the complete installation cycle of PET nonwoven geotextile on site. The instructions apply to all three weight variants, with specific notes where the technique differs.
Selecting the correct weight
Before ordering the material, confirm that the chosen weight corresponds to the application. 100 g/m² is suitable for gardening, mineral mulching, separation under decorative gravel, and residential filter trenches. 200 g/m² is the standard for civil engineering for separation between subbase and subgrade, road French drains, and low to medium traffic paths. 400 g/m² is reserved for geomembrane protection (HDPE in dams and landfills), audited hydraulic works, and areas with loose angular stone that can puncture lighter weights. Mix weights on the same site only when explicitly designed to do so.
Surface preparation
Clear the surface of roots, vegetation, and stones with sharp edges that could tear the geotextile when laid or covered with the upper material. For French drains, excavate the trench to the project depth and ensure the bottom has the minimum drainage slope (typically 1-2%). For separation under gravel, level the surface and compact if the natural soil is very soft. For geomembrane protection, remove sharp stones from the supporting soil that could puncture the membrane and ensure the surface is reasonably smooth.
Unrolling the geotextile
Unroll manually or with light machinery—the 5.95 m wide roll allows even a single person to handle most weights. Keep the fabric free of folds or wrinkles: a wrinkled nonwoven geotextile loses filtration effectiveness in the affected area. For trenches, extend it in a “U” shape covering the bottom, walls, and leaving 50 cm of excess on each side to wrap the aggregate later. For horizontal separation, lay it flat with the face up (in variants with a distinct manufacturing face) and ensure the roll unwinds without tugging that distorts the fabric.
Overlap at joints
When joining two rolls, overlap a minimum of 30 cm. In soft or saturated subsoils, increase the overlap to 50 cm to ensure the system maintains filtration continuity even if one of the two fabrics shifts during covering. For geomembrane protection, the minimum overlap is 50 cm without exception: a loose joint can leave the membrane exposed to localized puncture for decades. For French drains with complete aggregate wrap, the ends of the roll should overlap onto the trench bottom, not cut flush.
For French drains in trenches, the geotextile is installed as a complete wrap around the aggregate. The correct procedure is to excavate the trench, extend the geotextile so it covers the bottom, walls, and extends at least 50 cm on each side, fill with drainage aggregate (clean 1-2 inch crushed stone), fold the excess geotextile to close the "package" over the aggregate, and cover with natural soil. This complete wrap protects the drainage against fine migration for years. A geotextile placed only at the bottom of the trench loses effectiveness in a few seasons because fines enter from the sides and clog the aggregate.
Covering with the upper layer
Cover the geotextile with the material specified in the design without unnecessary delay—exposure to Caribbean sun degrades PET over time even with UV additive. For French drains, fill with clean drainage aggregate. For separation under decorative gravel, cover with the planned gravel layer, avoiding direct discharge of expensive aggregate from height onto the geotextile. For geomembrane protection, install the membrane over the geotextile with care appropriate to the specific system of each project. The general rule is not to leave the geotextile exposed to the sun for more than a few weeks.
Do not use non-woven geotextile as a structural reinforcement element. Its tensile strength is very low (typically between 5 and 15 kN/m depending on grammage), insufficient for MSE walls or heavy-load road bases. If you install it where the project requires woven geotextile or geogrid, the system will not perform as calculated and may collapse. The function of non-woven geotextile is filtration, separation, and puncture protection; never tensile reinforcement.
What grammage corresponds to your actual application?
The choice between 100, 200, and 400 g/m² depends on the top load, subsoil type, presence of sharp stones, and the required project audit. Overpaying for 400 g/m² in landscaping is wasteful; saving with 100 g/m² in hydraulic works is risky. Ask the virtual assistant with details of your application, and we will guide you to the correct grammage without over- or under-sizing.
Complementary products
To complement PET non-woven geotextile in drainage, separation, and geomembrane protection systems, the following products cover the most common adjacent needs:
Woven PET geotextile is the option when the project requires structural reinforcement in addition to separation: MSE walls, industrial platforms with heavy loads, reinforced slopes. Non-woven PP geotextile is the economical alternative for landscaping and agricultural drainage where the low creep of PET is not a critical factor. Biaxial PP geogrid is combined with non-woven geotextile as a double-layer system (separation plus reinforcement) in soft subgrades for audited road works. Metal rods serve as temporary anchors for the geotextile during spreading in windy or sloped areas, before covering with the top layer.
Maintenance and care
Buried non-woven geotextile under aggregate or soil layers requires no maintenance during its decades-long service life. What does require care is storage and handling prior to installation: rolls are stored horizontally on pallets or a smooth bed, covered from direct sunlight. PET is UV resistant but not immune—a roll exposed to Caribbean sun for several months loses surface properties and becomes brittle at the edges. Inspect each roll before lowering it to the construction site to identify permanent creases, cuts, or edge damage that may have occurred during transport.
During handling on site, avoid dragging rolls over sharp stones or live metal edges that could tear the inside of the roll. A 30 cm longitudinal cut in a 100 m roll is not visible until it is unrolled, at which point it is too late to claim from the supplier. If the functional system is critical (geomembrane protection, primary drainage), consider opening and visually inspecting each roll before spreading, especially thicker grammages which are the most expensive.
Frequently asked questions (FAQ)
Which grammage should I choose among 100, 200, and 400 g/m²?
The criterion is the severity of the environment: type of top load, presence of sharp stones, size of the aggregate in contact, and expected service life. 100 g/m² covers residential landscaping, mineral mulching, and light agricultural drainage. 200 g/m² is the civil engineering standard for road separation under granular layers, highway French drains, and low to medium traffic roads. 400 g/m² is reserved for geomembrane protection (HDPE in dams and landfills), audited hydraulic works, and areas with loose angular stone. If you are between two options due to reasonable doubts, increase the grammage: the additional cost of one step is usually less than the cost of reinstalling the system when the lower one failed.
Why PET and not PP for my application?
PET has low creep under continuous loads, a critical condition for hydraulic works and audited projects with a declared service life of decades (dams, landfills, road separation under serious paved roads). PP is slightly less creep resistant but lighter, more manageable, and alkali resistant (useful in agribusiness with fertigation and basic soils). For landscaping, agricultural drainage, and light construction, non-woven PP geotextile performs at a lower cost. For hydraulic works, geomembrane protection, and road projects with structural auditing, PET is the correct choice.
How many m² does one roll yield and how do I calculate how many I need?
A 5.95 × 100 m roll is equivalent to 595 m² nominal. To calculate the actual number of rolls, account for overlap: in standard construction with 30 cm overlap, efficiency is 90 to 92%. For a 1000 m² surface, calculate between 1.85 and 2 rolls. For French drains with full aggregate wrapping, geotextile consumption per linear meter of trench is approximately double the basic perimeter of the trench (because it covers the bottom, walls, and closes at the top); calculate trench meters × (perimeter × 1.05 to include overlap) for a more precise estimate.