Infiltration for Impervious Surfaces

Skeletank Solutions for Infiltration with Impervious Surfacing

According to The Building Regulations 2000 H3, impervious surfacings should be ‘freedraining’ if possible i.e. paths, driveways or other narrow areas of paving should drain to, ‘pervious areas such as grassland’. If this is not possible, then the use of pervious surfacings should be explored. However, in many cases, impervious surfaces cannot be ‘freedraining’ and pervious surfacings are impractical. In these instances provision will need to be made to drain impervious surfaces to an underground drainage system.

Skeletank solutions for using SuDS in conjunction with impervious surfacings include the utilisation of the aggregate sub-base layers below the surfacings to provide storage if required (a suitable highly voided aggregate, such as Aggregate Industries SudsAgg or similar, should be used). When using this technique, increased volumes of storage can be accommodated by including components from our range of proprietary underground storage media as and where appropriate.

If you are using the aggregate layers below your impervious surfacings to temporarily store rainwater and then allowing it to soak away, it may be possible to have this construction within 5m of building foundations, (although ground conditions should be thoroughly investigated to ensure their suitability for this).

View the fact sheet USING SUDS CLOSE TO BUILDINGS.

 

Impervious Pavement Design Utilising Aggregate Layers for Storage and Incorporating Skeletank HPDC Units.

Skeletank HPDC Units provide designers with an ideal solution for diffusing rainwater into and out of the permeable aggregate layers* below impervious surfacings. They are available in two modular sizes (see below).

Skeletank HPDC Units are fully compliant with the requirements of BS7533-13:2009 Annex B, ‘Typical physical properties of replacement systems (geo-cellular) units’:

SELH02003 – 708 x 708 x 150mm deep, for catchments up to 100m2
SELH02001 – 2124 x 354 x 300mm deep, for catchments up to 250m2

Infiltration for impervious surfacing

The aggregate layers beneath an impervious surface when using this technique provide one level of treatment, which satisfies Section 2 of the optional Water Quality Criteria in Category 4 of The Code for Sustainable Homes and thus gains one additional credit (if required).

*Note: when using this technique a suitable highly voided aggregate – e.g. Aggregate Industries SudsAgg or similar – should be used.

 

Skeletank products shown in this example

SELH02003

SELH03002

SELH05002

SELH-05003-Charcon-Permafilter-Geotextile

SELH05003

 

Note: Specification options for Geotextiles are a choice of either SELH05002 HydroWMS Permatex HD 300 Geotextile or SELH05003 HydroWMS Permafilter Geotextile.

 

 

Impervious Pavement Design Utilising Aggregate Layers for Storage and Incorporating SEL HPDC Units to Supplement Storage Volumes.

If the permeable aggregate layer* beneath your impervious surface is not providing sufficient storage to meet volume requirements (usually due to low permeability of underlying subsoils), but increasing the depth of aggregate to provide more storage is a problem (e.g. because of high water tables, or other factors restricting excavation) then the larger of the two Skeletank HPDC Units (SELH02001) can be utilised to increase storage volumes, within the aggregate layer, without increasing excavation depths.

SELH02001 – 2124 x 354 x 300mm deep

C-HPDC-infiltration-impervious-extra-storage V-01.2

The aggregate layers beneath a pervious surface provide one level of treatment, which satisfies Section 2 of the optional Water Quality Criteria in Category 4 of The Code for Sustainable Homes and thus gains one additional credit (if required).

Note: when using this technique a suitable highly voided aggregate – e.g. Aggregate Industries SudsAgg or similar – should be used

 

Skeletank products shown in this example

SELH02003

SELH02001

SELH03002

SELH-05003-Charcon-Permafilter-Geotextile

SELH05002

SELH05003

 

Note: Specification options for Geotextiles are a choice of either SELH05002 HydroWMS Permatex HD 300 Geotextile or SELH05003 HydroWMS Permafilter Geotextile.