StormMaster is an extremely strong modular water-permeable polypropylene unit with a large storage capacity.

The StormMaster has been designed specifically to meet the needs of sustainable construction as advocated by the UK Government and provides the means for rainwater, collected from roofs and pavements, to be infiltrated into the soil. The sewage system is relieved of additional loads and drying out of the sub-surface can be prevented.

These underground storage units are wrapped in a heavy duty non woven, needle punched geotextile to allow water discharge to the subsurface, but do not allow soil or sand particles to go through.


Prevents extreme peak flows to main drainage and water purification systems

Rainwater is “cleaned” by geotextile surround

Economic to install

Decreases flooding during heavy rain falls

Promotes the balance in the groundwater position

Decreases environmental problems caused by development

Choice of many diameters for incoming pipes​

Flexible - can easily be expanded in all directions

Enables rapid construction of large storage capacities (95% voids)

Applicable for both high and low groundwater situations

Typical Applications

  • Car Parks
  • Landscaped Areas
  • Recreational Areas
  • Amenity Areas
  • Caravan Sites

Offering dramatic savings against traditional ring soakaways this system is increasingly popular with developers and specifiers as part of their response to the National Planning Policy Framework (NPPF) legislation (replacing both PPS3 and PPS25).

Technical Information

Nominal Size: 1.0m (W) x 1.0m(L) x 0.4m(H), 2.5 units/ m3, Weight/unit: 16.8 kg (Heavy Duty), 16.2 kg (Landscape), Vertical Strength: 400kN/m2 (Heavy Duty), 200kN/m2 (Landscape), Lateral Strength 90kN/m2, actual volume: 385 litres, Void ratio: 95.8%

The above data indicates typical values – comprehensive independent physical test data on the structural and hydraulic properties of the system is available on request.


Following detailed assessment of the required volume of stormwater to be stored (see CIRIA C753 & C768, R156D & BRE 365). The total number of StormMaster units can be calculated using 2.5/m3 (958 litres/m3 @ 95.8% void ratio). Decide on the best configuration for the characteristics of the site in question and create the “box” accordingly using the length and width dimensions. As a guide units require approx 0.5m of cover in landscaped areas and typically 0.75m cover in vehicular areas with a 75mm sharp sand base.


The standard StormMaster crates are available in two forms: Inners & outers. This allows large structures to be created with a closed fully assembled crate around the periphery of the structure. The inner crates (without sides) are supplied on efficiently stacked pallets to reduce transport and are simply placed inside the outer periphery crates a half layer at a time and clicked in place to form the inner structure. This does not affect the load bearing capability of the finished structure and allows water to flow in a three-dimensional way throughout the structure without the impediment of sidewalls. Maintenance procedures (visual inspections, jetting etc) can therefore be carried out simply and effectively at multiple points throughout the structure.

Complimentary Products

  • Geomembrane – provides a sealed surface to prevent infiltration
  • Geotextile – allows infiltration and protects the geomembrane
Contact us

Contact us to request a free sample

Scroll to Top