Don & Low geosynthetics can be used for a range of applications and requirements. If you are needing a product that provides adequate separation and filtration, or something that will help reinforce, we are certain we can help you. From gardens to motorways, horse menages to working platforms, our expert team are on hand to help.

Don & Low Ltd supplies a broad Lotrak® range that includes woven geotextiles, needle-punched nonwoven geotextiles, biaxial geogrids, reinforcement geotextiles, warning/marker products and silt fence solutions for civil engineering, construction and landscaping applications.

Lotrak® is the trade name used by Don & Low Ltd for its geotextile & geogrid products. In practical terms, LOTRAK is used across separation, reinforcement, filtration, erosion protection and drainage applications depending on the product type and the project requirements.

No. The geosynthetic is one part of the system as whole. Ground condition, drainage, loading, aggregate quality, layer thickness and installation quality still govern whether the final construction performs as intended.

For everyday separation and filtration requirements, Don & Low offers a range of mechanically bonded nonwoven geotextiles such as Lotrak® 80, 100, 140, 160, 200 and 300. For example, Lotrak® 100 is described as a market-leading nonwoven geotextile for routine separation and filtration needs beneath selected granular materials.

For reinforcement applications, Don & Low offers both reinforcing woven geotextiles such as Lotrak® 50R and 70R, and biaxial geogrids such as Lotrak® 20/20S, 30/30S, 40/40S and 30/30L. These products are designed to improve ground stability, distribute loads and help reduce the thickness of imported aggregate where appropriate.

Lotrak® 50R and 70R are reinforcing woven geotextiles used where reinforcement is required in addition to separation and, depending on the application, filtration benefits. They can be used for applications with weak subgrades and help distribute traffic-induced stresses, helping provide a multi-function solution in certain road and platform applications. Lotrak® 50R and 70R are exceptionally good for floating road applications, where access over very soft ground with little vegetation disruption is required.

Yes. Lotrak® geotextiles and geogrids for use in road construction, paved and unpaved roads, access roads, working platforms, loading bays and car parks. This is consistent with broader sector use of geogrids and geotextiles for temporary and permanent traffic-bearing layers over weak or variable subgrades.

Depending on the design, subgrade condition and selected product, Lotrak® geogrids can help improve bearing capacity and load distribution, which in turn commonly allows a reduction in the thickness of imported aggregate compared with an unreinforced construction.

Yes. Lotrak® geotextiles are manufactured in the UK, and Don & Low Ltd positions itself as a long-established UK manufacturer of woven and nonwoven technical textiles. We are the only UK manufacturer of both woven and nonwoven geotextiles.

This is a common question asked by clients. Lotrak® geogrids are a premium geogrid, offering a product design life of 100 years. This makes our geogrids the ideal choice for both permanent and temporary applications leading to easier product selection, specification and single stocked SKU no matter the design life requirement.

A geosynthetic is a manufactured polymer-based product used in civil engineering or geotechnical works to improve the performance of soil, aggregate, water control systems, or pavement structures. The term covers products such as geotextiles, geogrids, geonets, geomembranes and geocomposites.

The main functions usually include separation, reinforcement, filtration, drainage, protection and erosion control. Not every product performs every function equally well, so product selection should be based on the dominant design requirement.

They can improve performance, reduce contamination of aggregate layers, assist constructability over weak ground, and in some applications reduce the required thickness of imported fill. They may also help reduce excavation and transport requirements when correctly designed. Further to this the use of geosynthetic products can reduce the cost of raw materials, installation (less movement/fill material needing to be placed and compacted) & duration of the project, can extend the design life of an application (e.g. Road) and by doing so will reduce the environmental impact and CO₂ emissions made from transportation.

No. They are one component of a system. Overall performance still depends on subgrade condition, drainage, loading, aggregate quality, layer thickness, installation quality and compliance with the project specification.

They can in some applications when supported by a Don & Low conceptual design. Reinforcement products such as the Lotrak® geogrid range can lead to a reduction in aggregate thickness, but any reduction should come from the recognised design approach or project-specific design submission, not from assumption. Don & Low’s technical team can help assist in the conceptual design process.

A geotextile is a permeable polymeric textile used in civil engineering, landscaping and geotechnical applications. Depending on the product and the application, it can act as a separator, filter, drainage medium, erosion control layer, or reinforcement element.

Yes—if the product has been selected for the hydraulic conditions and installed correctly. Geotextiles are permeable materials, but the water flow capability depends on the product structure, thickness, opening size, and the surrounding soil/filter system.

A properly selected geotextile should retain enough soil to create a stable filter interface while still allowing water to pass. If the openings are too large, soil loss may occur. If too small, clogging risk can increase. That is why filtration applications should be selected against soil grading and hydraulic conditions rather than by weight alone.

Lotrak® geotextiles are typically selected because they are durable and resistant to biological decay. They are not chosen because they “rot away”; they are chosen for service performance over the intended design life.

Yes. Like many polymeric products, prolonged UV exposure can reduce performance. Geotextiles should usually be covered as soon as practical in accordance with the product guidance and project requirements.

No. Weight on its own is not a design method. Mechanical properties, puncture resistance, opening size, permeability/flow characteristics, durability and the intended function all matter.

No. geotextiles should not be compared in terms of weight and thickness alone because those values do not directly define performance.

They are woven polypropylene geotextiles used as an excellent separator or reinforcement product used for a wide range of civil engineering applications. The main purpose of this geotextile is to prevent the loss of larger

construction aggregates into the underlying subgrade. The Lotrak® range is described as woven fabrics made from polypropylene tapes. Lotrak Base, 2300 and 2800 as general purpose grades, 50R and 70R identified as reinforcing fabrics depending on ground conditions. Don & Low also manufacture our leading Lotrak® Alarm 15 indication product – a bright orange geotextile used as a warning separation layer.

When robust separation, reinforcement-related performance or maintaining the integrity of aggregate over weaker ground. Final grade selection still needs the project inputs and the relevant design method.

Woven geotextiles are formed by interlacing tapes, yarns or in a regular pattern. Non-woven geotextiles are formed from fibres that are thermally and mechanically bonded (needle-punched( together. Their structures are different, so their mechanical and hydraulic behaviour can be different as well.

In simple terms, woven geotextiles are generally selected where higher tensile performance and robust separation/reinforcement are required, while needle-punched nonwoven geotextiles are typically chosen where filtration, drainage and separation are key priorities. Don & Low’s Lotrak® range includes both woven and nonwoven solutions so the specification can be matched to the required function.

Woven geotextiles are commonly selected where high tensile strength, robust separation, and low elongation are important—such as trafficked working platforms, haul roads, access tracks, and subgrade separation where mechanical performance is critical.

Non-woven geotextiles are commonly selected where filtration, cushioning/protection, or drainage-related behaviour is important. Needle-punched non-wovens are also widely used for separation in many civil works, depending on the design criteria.

No. The correct choice depends on the function. Woven may be advantageous for strength and certain separation/reinforcement applications, while non-woven may be better suited to protection or some filtration/drainage roles. The product should match the design function.

Not always. Woven products often rely on a more regular opening pattern and a stable bridging mechanism at the interface. Non-wovens can behave differently because their pore size distribution is more variable and some can be more susceptible to clogging if not selected carefully.

No. Product substitution should only be made after reviewing the relevant design criteria and performance requirements. Apparent similarity in mass per unit area does not prove equivalence. Please speak to our technical team should you wish to switch grades.

A geogrid is a polymeric geosynthetic with an open grid structure that works by allowing aggregate to interlock within its apertures, helping to improve confinement, spread load and reduce lateral movement in the granular layer.

A geogrid is primarily a reinforcement or stabilisation product with open apertures for interaction with surrounding aggregate or soil. A geotextile is a permeable textile that may perform separation, filtration, drainage, protection or reinforcement depending on the product. Some projects use both together because they perform different functions.

A geogrid is usually considered when the main objective is stabilisation and reinforcement through aggregate interlock and load distribution, whereas a geotextile is usually selected when separation, filtration and drainage are the primary needs. In some cases, both products may be used together so that each performs a different function within the same pavement or platform build-up.

Yes. In ground stabilisation and working platform applications, it is common practice for a geotextile separator/filter to be placed against the subgrade and the geogrid above it so the aggregate can interlock properly with the grid. This layered approach is widely referenced in installation guidance across the sector.

Biaxial geogrids are designed to provide reinforcement capability in two principal directions and are commonly used where load distribution in a granular layer is required in more than one direction.

Not automatically. A geogrid may provide reinforcement, but it does not provide the same separation or filtration function as a geotextile. In some designs the two products are used together because each solves a different problem.

Typical applications include Paved Roads, Unpaved Roads, Working Platforms, Sports Pitches to name a few. They are also used in cases where general subrage improvement or reduction is required. Speak to our technical team today to find out how our “Stronger by Design Service” can help find the right solution for you.

The aperture geometry affects how aggregate interlocks with the grid and how load is transferred. Geogrid performance depends not only on tensile properties, but also on junction strength, geometry and compatibility with the fill material.

Don & Low’s Lotrak® biaxial geogrid range includes 20/20S, 30/30S, 40/40S and 30/30L. These grades are intended for ground reinforcement across both temporary and permanent applications, with different strengths and aperture characteristics to suit the design requirement and aggregate size.

These grades differ primarily in their tensile strength and aperture configuration. For example, Lotrak® 20/20S is positioned as an entry reinforcement grade for stabilisation and bearing improvement, while 30/30S and 40/40S offer higher strength, and 30/30L has larger apertures to suit larger aggregate and specific interlock requirements. It is important to note that tensile strength does not always account for design requirements. Substituting one biaxial geogrid for another can have a big impact on the construction build up – such as paved and unpaved roads. The design methodologies used in these applications, do not consider the general kN tensile strength of the product.

Not automatically. A woven reinforcement geotextile and a geogrid are not always direct substitutes, because they are typically selected for different primary functions within the construction build-up. Geogrids are open, grid-like reinforcement products used where interaction with aggregate or soil is needed to mobilise reinforcement, while woven geotextiles are textile products that may be used for separation, filtration and, in some cases, reinforcement depending on the product and application.

A woven reinforcement geotextile may be suitable instead of a geogrid only if the design function, loading conditions, ground conditions and project requirements are all still satisfied. The safest position is that the product should be selected based on the required function in the design, not treated as a like-for-like swap.

A geogrid is generally the more appropriate choice where the design is relying on reinforcement within the aggregate layer, particularly where biaxial reinforcement is required in two principal directions.

A woven geotextile can be suitable where the main requirement is separation, filtration, or an appropriate woven reinforcement fabric solution, provided the design confirms it meets the required performance for the site conditions and application.

Start with the primary function. If the dominant requirement is reinforcement within aggregate, a geogrid may be appropriate. If robust separation and tensile performance are key, a woven geotextile may suit. If filtration, protection or cushioning is dominant, a non-woven may be more suitable. Many applications require more than one function, so the final choice should be design-led.

Typical inputs include:

• Subgrade strength (for example CBR or undrained shear strength where appropriate)

• Traffic loading

• Number of passes

• Allowable rut depth (where relevant)

• Aggregate properties

• Drainage/hydraulic conditions

• Construction method

• Durability requirements and any specification clauses that must be met

Inputs may differ depending on the application being considered. It may be best to view our questionnaire to find out what inputs are specifically required, for a conceptual design to be run to specify what materials would be required for the specific projects.

In some designs, yes. Where reinforcement and/or separation benefits are mobilised, a reduction in required aggregate thickness may be achievable. However, any reduction must come from a recognised design method or project-specific design submission.

Not on their own. They can form part of a drainage or filtration solution, but if standing water, seepage or poor outfall conditions remain unresolved, the overall system can still fail.

Where possible, selection should be based on the required performance criteria for the application and backed up by a manufacturers Declaration of Performance document. Many products and quotations are provided with a data sheet, however, to ensure you are certain of the manufacturer and the products reported properties, you should always request a Declaration of Performance. This is backed up by in the latest recommendations set out in BS8661 - Geotextiles: Guidance for specification for basic separation and filtration functions.

Typical checks include:

• Subgrade suitability

• Proof rolling (where specified)

• Adequate drainage

• Aggregate quality

• Layer thickness

• Trafficking limits during construction

• Overlap requirements

• Damage control and any post-installation validation tests required by the design/specification.

For over 42 years Don & Low have been providing engineers, contractors and clients the technical support and guidance they need when it comes to Lotrak® products and applications. Our Stronger by Design Service started back in 1984 to provide conceptual design & technical support assessments. Our engineering team use the project information provided by you to prepare a preliminary geosynthetic conceptual design solution. This typically includes an outline recommendation for the proposed materials and construction thickness/build-up for the site, based on the design inputs available at that stage.

Don & Low’s Lotrak® conceptual design documents are intended to provide a suitable project-specific solution based on our Lotrak® products. These conceptual designs are not a substitute for the responsibilities of the overall scheme designer or professional advisors. For more information or to book a Stronger by Design consultation with one of our engineers, please contact us.

A professional indemnified design service is a project-specific design carried out by qualified engineers and backed by Professional Indemnity (PI) insurance. It provides a formal design recommendation based on the information supplied for the project, offering greater assurance than a general product suggestion.

Yes. Don & Low Ltd can offer a Professional Indemnified (PI) Design service through a trusted third-party consultant. This service is available at an additional cost.

Don & Low’s installation guide should be followed. It advises that the prepared surface should be cleared of large protrusions and significant irregularities, then the geotextile should be rolled out with minimal wrinkles, positioned correctly, and protected from damage during aggregate placement. Vehicles should not travel directly on the exposed geotextile.

The subgrade should normally be inspected before installation. Very soft spots, organics, peat, deleterious material, protruding objects and major depressions should be addressed in line with the project design or specification before the geosynthetic is covered.

The subgrade should be proof rolled and carefully inspected before laying the geotextile, and that any soft or deleterious materials should be removed and replaced with additional compacted granular fill in that project context.

It should generally be laid flat and in good contact with the underlying surface, minimising folds or wrinkles while still allowing the product to follow the contours of the formation.

As a general rule, the geosynthetic should be protected promptly by the specified cover layer. Construction traffic should not be allowed to operate directly on an exposed geosynthetic unless the project-specific method statement and manufacturer guidance explicitly allow it.

For Lotrak® geotextiles, it is recommended that a minimum 300 mm depth of fill is placed before compaction or trafficking. This aligns with the general industry principle that geosynthetics should be protected by sufficient initial cover before plant movement is allowed over the reinforced or separated layer.

This must follow the project-specific design, product guidance and subgrade condition. In some project documents, simple overlaps of 300 mm are specified; in softer ground, greater overlaps may be required. Do not assume one overlap value is universal for all products and all ground conditions.

Table below can be used as guidance:

Don & Low’s geotextile installation guidance states that Lotrak® geotextiles should be covered within 1 month of installation and should not be exposed to direct sunlight for more than 30 days. Don & Low’s geogrid datasheets also note that the geogrids should be covered within 1 month of installation.

Stop and review the situation against the design assumptions. Soft spots or deleterious material may need to be removed and replaced, drainage measures may be needed, or the design may need to be reviewed before work continues.

The initial cover thickness and placement method must follow the design and installation guidance. For soft ground projects, the first lift is commonly placed carefully to avoid damaging the geosynthetic and to prevent punching or further weakening of the subgrade.

Aggregate should be spread in a controlled manner to prevent damage, maintain overlaps and avoid dragging or displacing the product. The approach should follow the project specification, method statement and the product guidance.

Immediate repair should be administered; damaged areas should be assessed and repaired in accordance with the project requirements and manufacturer guidance before the next stage proceeds. The design intent should not be compromised by leaving damage unattended.

Very important. Standing water, seepage, poor outfalls or saturated weak subgrades can significantly affect constructability and performance. Temporary drainage measures may be needed during the works.

Yes. Don & Low states that certain Lotrak® geogrids can be used to increase the bearing capacity of underlying soils and can also be used to construct mattresses on soft soils.

Yes. On very soft formations, aggressive or vibratory compaction can worsen conditions by increasing pore pressures or causing further disturbance. Compaction method and sequencing should follow the design/specification, especially on weak saturated ground.

Work should stop and the design assumptions should be reviewed. Calculations should be re-assessed and the “softer ground” should be tested so that the new and site-specific values are used for the assessment. Furthermore, if its only small areas, the soft or deleterious material should be removed and replaced where encountered. Please contact our technical services team for more information.

Yes. Don & Low states that its Lotrak® geogrids are predicted to be durable for more than 100 years in soil temperatures of 25°C or below, and that they are resistant to highly acidic and alkaline environments on the basis of durability assessment.

Yes. Don & Low’s product pages and Lotrak® range pages is where you can find downloadable CE and/or UKCA documentation for multiple products, including geotextiles and geogrids.

For project-specific advice, specification support or product selection assistance, you can contact the Lotrak® technical team direct through the contact us link through our enquiry channels and technical support routes.

Typical checks include product identification, roll labels, product grade, dimensions, visible damage, storage condition and conformity with the approved product schedule or design submission.

They should be stored cleanly, securely and protected from unnecessary damage or prolonged exposure before use. Storage should follow manufacturer recommendations and the site quality plan.

Useful records include product batch/roll references, installation dates, area installed, weather/site condition, overlap arrangement, photographs, inspection results, any repairs made and any departures from the original method.

Commonly overlooked items include confirming the actual subgrade condition at formation, checking whether overlaps have been maintained during fill placement, checking for torn or displaced areas, and confirming that specified aggregate and layer thicknesses have actually been achieved.

Yes. Failures can still arise from poor drainage, wrong aggregate, inadequate thickness, excessive trafficking, unexpected ground conditions, poor compaction control, or installing a correct product into the wrong application.

Yes! product selection is strongest when supported by the project information, intended function and relevant design criteria. A technical review is always preferable to selecting from a product list alone.

Yes, provided the comparison is based on appropriate performance properties, test methods and the application requirements.

No. Ground conditions, loading, drainage, traffic and specification requirements vary from project to project, so product choice should always be tied to the specific application.

Ask for the missing inputs. For example: subgrade CBR/strength, traffic, aggregate depth, groundwater/drainage, temporary or permanent application, and the required design life or performance criteria.