What is geotextile material?

Geotextile material is a specialist fabric used in construction, landscaping, and civil engineering. It can help to improve ground stability, manage water flow, and protect structures. Often referred to as geotextile fabric or geotextile membrane, this durable material is designed to perform essential functions such as separation, filtration, reinforcement, and drainage. Understanding what geotextile is, the different types of geotextile membrane available, and what geotextiles made of, can help you choose the right solution for your project. 

This guide covers the key differences between products, including what is the difference between woven and non woven geotextile, the difference between geotextile and geomembrane, and what is geocomposite, along with practical advice on how and where geotextiles are used. 

What are geotextiles made of? 

Geotextiles serve a wide range of applications, but what are they made of? Manufacturers use either natural or synthetic fibres, with polypropylene and polyester among the most common materials used in modern construction and landscaping projects.

Natural fibre geotextiles

Historically, natural fibre geotextiles such as jute have been widely used. However, coir—derived from coconut husks—has become increasingly popular due to its improved durability. While jute is a vegetable fibre that biodegrades relatively quickly, it often requires synthetic treatments to extend its lifespan. Coir, by comparison, offers greater natural resistance to decomposition, making it a suitable choice for short- to medium-term applications, particularly in erosion control. 

Types of synthetic geotextile material

Most permanent installations now rely on synthetic geotextiles due to their strength, durability, and resistance to environmental factors. These are typically made from materials such as polyester (PET), polyethylene (PE), and polypropylene (PP). Manufacturers use polymerisation to increase the structural integrity and service life of polyester geotextiles. With the right conditions, some products last up to 50 years. Polyethylene plays an important role in products that provide containment and barrier functions. 

In some designs, woven and non-woven polypropylene geotextiles are combined with other components. This is to provide additional functionality, such as improved protection against root intrusion. Combining different materials in this way creates what is known as a geocomposite, which is explained later in this guide. 

What is the difference between woven and non-woven geotextile? 

Geotextiles are generally divided into two types: woven and non-woven. Both are widely used in construction and landscaping projects across the UK. However, they are manufactured by different methods and behave differently once installed. The difference between woven and non woven geotextile is an important consideration when selecting the most suitable material, as the right choice can affect the strength, stability, drainage, and overall performance of a project. Factors such as load-bearing requirements, water flow, and ground conditions will often determine which type is most appropriate.

Non-woven geotextiles are made by bonding fibres together using mechanical needling, heat, or chemical processes. This creates a soft, felt-like fabric that is highly permeable, allowing water to pass through while preventing soil and other particles from migrating. Non-woven geotextiles are widely used in UK road construction for separation and filtration, helping prevent the intermixing of sub-base and subgrade layers while supporting drainage within the pavement structure. They are also extensively used in railway construction and maintenance, where they help to separate ballast from underlying soils and manage water movement—meeting specifications set by organisations such as Network Rail and Transport for London (TfL). Additionally, non-woven geotextiles are commonly applied in soakaways, French drains, and beneath permeable paving, where water management is essential.

Woven geotextiles are produced by weaving synthetic fibres together in a regular, criss-cross pattern. This creates a fabric that is exceptionally strong and durable, with high tensile strength. Woven geotextiles are typically chosen where reinforcement is required, particularly over weak or unstable ground, helping to distribute loads and reduce pressure on underlying soils. They are often specified for stabilising sub-base layers in areas with soft ground conditions, as well as for haul roads and working platforms. While they allow limited water movement, their semi-impermeable design makes them ideal where structural support is the priority over filtration.

What is geocomposite and how does it differ from geotextile? 

A geocomposite is a type of geosynthetic material that combines two or more different products to deliver enhanced performance for construction and environmental projects. Most commonly, geocomposites include a geotextile layer paired with materials such as drainage cores, geomembranes, or geogrids. By combining these components, geocomposites are designed to offer multiple functions within a single system.

While traditional geotextiles are used for specific tasks like separation, filtration, or reinforcement, geocomposites integrate several of these functions at once. For example, a drainage geocomposite might feature a geotextile layer for filtration alongside a structured core that provides a direct pathway for water to flow. This makes geocomposites particularly useful in complex applications such as landfill drainage, retaining wall systems, and tunnel linings, where both filtration and drainage are required in the same area.

Some geocomposites combine geotextile layers with materials that introduce an additional function. For example, CuTex incorporates woven and non-woven geotextiles with a copper sheet. In this case, the geotextile layers manage filtration and separation. The copper creates a chemical barrier, releasing copper ions that inhibit root growth. This creates a system that allows water to pass through while protecting nearby structures and services from root intrusion.

The key difference between geocomposite and geotextile products is the level of functionality they provide. Geotextiles are single-layer materials designed to perform one main purpose, whereas geocomposites combine multiple layers and materials to increase efficiency, reduce installation time, and minimise the need for separate products on site. 

The difference between geotextile and geomembrane 

It is useful to understand the difference between geotextile and geomembrane, as each serves a different purpose in construction and environmental projects.

Geotextiles are typically permeable fabrics used in applications where filtration, separation, reinforcement, or drainage is needed. Their structure usually allows water to pass through while preventing the movement of soil and other particles, making them suitable for use in road construction, soakaways, and erosion control. However, it's worth noting that geotextiles can vary in permeability. Whilst most are designed to be permeable, some geotextiles (sometimes referred to or categorised as 'non-permeable') have lower permeability for specific applications like silt fences or temporary fluid barriers. Even these 'non-permeable' geotextiles, however, are generally more permeable than geomembranes.

Geomembranes, on the other hand, are designed to be ultra-low permeability barriers that significantly restrict the movement of liquids and gases. While not absolutely impermeable, their permeability is so low it's often measured in nanometers, making them 1,000-10,000 times less permeable than even the least permeable geotextiles. They are typically used in situations where containment is critical, such as landfill liners, ponds, and reservoirs, helping to minimize seepage and protect the surrounding environment.

In some cases, geotextiles and geomembranes are used together to provide both filtration and containment. Alternatively, geocomposites combine different materials into a single product, offering multiple functions within one system.

The table below provides a comparison of geotextiles, geomembranes, and geocomposites, highlighting how they differ in function, material, and typical applications.

Aspect	Geotextiles	Geomembranes	Geocomposites
Function	Typically permeable fabric for filtration, drainage, separation, and reinforcement. Some specialised types have lower permeability.	Ultra-low permeability barrier designed to significantly restrict liquid and gas movement.	Multifunctional material combining geosynthetics for drainage, reinforcement, or containment.
Material	Woven or nonwoven polypropylene or polyester fibres.	Polyethylene (HDPE, LLDPE) or PVC for impermeability.	Combination of geotextiles, geomembranes, or geogrids in layered systems.
Applications	Road construction, erosion control, and drainage systems, and specialised applications like silt fences.	Landfill liners, ponds, reservoirs, and hazardous material containment wher near-zero seepage is required.	Landfill drainage, tunnel walls, root control and projects needing combined reinforcement and filtration.
Key Benefit	Cost-effective and versatile for filtering, reinforcing, and protecting soils. Permeability can be tailored to specific needs.	High durability and impermeability for containment solutions.	Combines functions into one product for complex and specialised applications.

Functions of geotextile membranes 

Geotextile membranes are used in a wide range of projects due to their ability to perform several important functions, often simultaneously. These functions help improve the performance and longevity of construction and landscaping works by managing the movement of water, soil, and other materials.

Separation – Geotextile membranes prevent different layers of soil from mixing. This helps maintain the integrity of structures by keeping the base materials stable and reducing the risk of settlement over time.

Filtration – While keeping soil layers separate, geotextiles allow water to pass through. This controls water movement while filtering out fine particles, which helps to prevent blockages in drainage systems.

Reinforcement – By adding strength to weak or unstable ground, geotextiles help distribute loads more evenly. This improves the bearing capacity of the soil and supports structures such as roads, paths, and retaining walls.

Protection – Geotextiles can act as a protective layer, shielding underlying materials like geomembranes from punctures, abrasion, or damage caused by sharp objects or heavy loads.

Drainage – Geotextile membranes assist with water management by helping to direct water away from structures and into designated drainage systems, reducing the risk of waterlogging and erosion.

By performing these functions, geotextile membranes help to create durable, stable, and long-lasting solutions across a variety of applications, from infrastructure projects to landscaping schemes.

Applications of geotextiles

Geotextiles are widely used in construction, landscaping, and environmental applications.

In construction, geotextiles are commonly used for road building, retaining walls, and foundation support. By reinforcing the ground and separating different layers of material, they help to extend the lifespan of these structures and reduce maintenance requirements.

In landscaping, geotextiles provide soil stabilisation, erosion control, and effective drainage. Their permeable design allows water to pass through while filtering out particles, helping to prevent waterlogging and surface damage. They are often used beneath paths, patios, and driveways to improve ground conditions and maintain surface stability.

In environmental applications, geotextiles are used to protect natural and engineered landscapes. This includes coastal protection works, landfill liners, and large-scale erosion control systems, where they help prevent soil loss and safeguard surrounding areas from damage. 

How to choose the right geotextile for your project

Selecting the right geotextile depends on the specific requirements of your project. Some of the key factors to consider include:

1. Project type – The demands of road construction, drainage, landscaping, or erosion control will influence the most appropriate geotextile.
   
   
2. Soil conditions – Understanding the type and stability of the ground will help determine the level of reinforcement or filtration needed.
   
   
3. Load and stress – Consider the weight and pressure the geotextile must withstand, particularly in high-traffic or heavily loaded areas.

For more complex projects, it is often beneficial to seek expert advice to ensure the correct material is chosen. At Root Barrier Store, we can provide guidance on product selection to meet a wide range of requirements.