- What is a geomembrane?
- What is HDPE?
- What is LLDPE?
- Key differences between HDPE and LLDPE
- Which membrane is best for attenuation tanks?
- Flexibility and installation considerations
- Durability and puncture resistance
- Typical applications for each material
- Frequently asked questions
What Is a Shoebox Liner for an Attenuation Tank?
When constructing an impermeable attenuation tank, one of the most important components is the liner system that surrounds the attenuation crates. Often referred to as a shoebox liner, this factory-fabricated geomembrane enclosure creates a waterproof barrier around the storage system, allowing stormwater to be temporarily stored and released at a controlled rate.
Shoebox liners are widely used within Sustainable Drainage Systems (SuDS), commercial developments, highway drainage projects and stormwater storage schemes where infiltration into the surrounding ground is not permitted or practical.
Why Is It Called a Shoebox Liner?
The name comes from its appearance.
A factory-fabricated liner is typically supplied as two separate sections:
- A base section that contains the attenuation crates
- A lid section that folds over the top
Much like the base and lid of a shoebox, the two sections work together to create a fully enclosed storage system.
This approach helps simplify installation and reduces the amount of site welding required compared to traditional flat-sheet installations.
How Does a Shoebox Liner Work?
A typical impermeable attenuation tank build-up consists of:
- Excavation
- Attenuation crates
- Geomembrane lid section
- Protection fleece
- Backfill
The geomembrane liner prevents water escaping into the surrounding ground while the attenuation crates provide the structural void required for stormwater storage.
Factory-installed top hat units can also be incorporated where inlet, outlet or vent pipes penetrate the liner system.
Benefits of a Factory-Fabricated Shoebox Liner
Faster Installation
Factory-fabricated liners arrive ready for installation, reducing the amount of cutting and welding required on site.
Reduced Installation Risk
Manufacturing under controlled factory conditions can improve consistency and minimise the potential for installation errors.
Improved Quality Control
Seams and penetrations can be fabricated and checked before delivery, helping to provide a consistent finished product.
Suitable for Large Projects
Shoebox liners are commonly used on commercial developments, industrial projects, highways schemes and large-scale SuDS installations.
HDPE vs LLDPE Shoebox Liners
Most shoebox liners are manufactured using either HDPE or LLDPE geomembranes.
If you’re unsure which specification is most suitable, read our guide comparing HDPE and LLDPE geomembranes.
HDPE Geomembranes
HDPE geomembranes offer excellent puncture resistance, chemical resistance and long-term durability, making them a popular choice for attenuation tank applications.
LLDPE Geomembranes
LLDPE geomembranes offer greater flexibility and can be beneficial where complex detailing or irregular shapes are involved.
The most suitable material will depend on the project requirements and design specification.
Do You Need Protection Fleece?
In most attenuation tank applications, protection fleece is installed above and below the geomembrane liner.
The fleece helps protect the membrane from puncture during installation and throughout the service life of the system.
A 300gsm non-woven geotextile protection fleece is commonly specified for this purpose.
We explain this in more detail in our article on whether attenuation tanks require protection fleece.
Information Required for a Shoebox Liner Quotation
To obtain a quotation for a bespoke attenuation tank liner, it is helpful to provide:
- Tank length
- Tank width
- Tank depth
- Attenuation crate manufacturer
- Pipe penetration details
- Site postcode
- Required delivery date
The more information provided at the enquiry stage, the quicker an accurate quotation can be prepared.
If you already have drawings available, our Bespoke Shoebox Attenuation Tank Liners service can be quoted directly from project plans and drainage layouts.
Bespoke Shoebox Attenuation Tank Liners
Drainage & Civils Direct supplies bespoke shoebox attenuation tank liners manufactured to project-specific dimensions. Available in HDPE and LLDPE geomembranes, liners can be supplied with protection fleece, top hat units and factory-fabricated detailing to help streamline installation.
If you have project drawings available, email them to info@drainageandcivilsdirect.co.uk and we will be happy to review your requirements and provide a quotation.
