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ABG Extensive Green Roof with Roofdrain 25mm Reservoir Board

Verified by manufacturer 24 days ago

ABG Third party certifications:
  • Carbon Footprint Standard

    Carbon Footprint Standard

    Certificate type

Extensive green roof system

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Extensive green roof build-up suitable for flat or pitched roofs and new or retrofit applications. The benefits of a green roof are wide ranging, such as helping to mitigate the effects of climate change by providing an urban cooling effect, reducing surface water run-off and filtering pollutants from the surrounding air, through to maximising BREEAM credits, or simply softening the visual impact of the building.

The successful establishment of vegetation is supported by the Roofdrain 25mm reservoir / drainage board to prevent drying out or waterlogging of the growing media.


Extensive Green Roof comprises:

- Growing media:

ABG peat free media derived from sustainable, 100% recycled, UK sourced materials. Using a specifically developed growing media can help provide the right growing environment for the selected vegetation and also reduce the load on the roof. The growing media can also be adjusted to support specific design requirements like calcareous applications.

- Vegetation:

Specifically selected to suit the final finish requirements of the client / end user. On extensive green roofs, low maintenance varieties such as mosses, herbaceous plants, sedums, wildflowers and grasses tend to be used.

- ABG Roofdrain:

Geocomposite reservoir board with multidirectional drainage function suitable for use underneath substrate layers of 150 mm and below. It is particularly useful on pitched roofs due to the profile of the cone shaped cuspates.

ABG Roofdrain allows the storage of water within the cuspates of the HDPE core, whilst facilitating the efficient drainage of any excess water away from the roof. This helps prevent the growing media from drying out or from becoming waterlogged. When used within a green roof construction, it provides a versatile system for the collection of rainwater at the base of the growing medium and for the prevention of water pressure on the structural waterproofing, whilst still allowing oxygen and nutrients to get to the roots of the plants.

Roofdrain consists of three components bonded together to create a single product. A filter textile is bonded to the upper part of the reservoir board to provide a separation layer that filters particles and fines down to 100 microns (µm), whilst preventing the substrate from any ingression into the reservoir layer.

The core is perforated to allow excess water to drain through into the flow channels underneath, preventing pooling and oversaturation of the plants. Finally, a protection geotextile is bonded to the underside of the reservoir/ drainage board to protect the insulation / waterproofing layer onto which the Roofdrain is placed.

Features and benefits:

  • Added protection for waterproofing layer
  • Scores BREEAM points
  • Reduces whole life costs of the building and energy usage
  • SuDS design solution, acting as the first stage in the treatment train
  • Creates a usable space
  • Creates habitat to improve biodiversity
  • Noise reducing
  • Extracts pollutants and improves air quality

General information




25 mm

Warranty description

Guidance for specification option:

Equal to the life of the green roof maintenance contract.


Ss_45_40_47_28 Extensive green roof systemsPrimary


Q37/130 Extensive green roof

Product range

Extensive Green Roofs

Specification data - Extensive green roof systems



Root barrier

To be determined by waterproofer.

Moisture control


Drainage layer

ABG Roofdrain 25.

Guidance for specification option:

25 mm thick.

Reservoir capacity: 4.3 L/m².

Filter membrane

Geotextile filter bonded to the upper part of the reservoir board.

Moisture retention mat

Drainage/reservoir board.

Drainage ancillaries

Protection geotextile bonded to the underside of the reservoir/ drainage board.

ABG Green Roof Access Chambers.

Guidance for specification option:

Purpose designed to create inspection chambers around outlets and irrigation points in green roof systems. They are manufactured from high grade powder coated aluminium offering excellent corrosion resistance. The base of chamber allows drainage via channels cut into the base. Both standard and parapet bases available in three different sizes of interlocking mid sections to cater for different levels of build-up. Each comes with a lockable lid.

Planting systems


Planting medium

A blend of water retaining aggregates, crushed brick and organic material.

Guidance for specification option:

Mixed to provide an extensive growing media to meet customer specifications. Extensive growing media is a versatile, lightweight general purpose green roof growing media, ideal for sedum matting systems and systems supporting hardier lower maintenance plants such as sedum, wildflowers and grasses.

Planting requirements

Mixture of sedum, wildflower turf and plug plants.

Manufacturer guidance

In accordance with the landscape design or ecology plan.

Edge restraints

ABG Abpro Aluminium Profiles.

Guidance for specification option:

Designed for use in variety of green or ballasted roof applications. They can be used either as an edge restraint, or where a solution for retaining or separating the roof garden materials is required. Lightweight and robust, they can be cut to length and angled to suit the roof design, are available powder-coated in any colour and are connected with plate connectors.



Manufacturer guidance

All operatives carrying out the vegetation installation should refer to the ABG installation and establishment guidelines for vegetation.

System completion

Establishment watering requirements: Surface watering for the first 10 weeks following installation (to ensure the substrate remains moist to the touch).

Guidance for specification option:

It is the responsibility of the roofing contractor to liaise with the main contractor/ building owner to provide water and ensure that the planted growing medium is thoroughly irrigated immediately after installation. An adequate mains water supply of sufficient pressure must be available and operational prior to the plants being installed.

Manufacturer guidance

ABG Installs' maintenance service

ABG's contracting business - ABG Installs - offers a professional maintenance service using experienced green/blue roof technicians and can provide an estimate for carrying out on-going maintenance. Contact the green roof maintenance team on Tel: 01484 354836.

Sustainability data

Embodied carbon

A1-A3 (production stage) as defined in BS EN 15804

1.72 kg CO₂ eq/kg

BIM objects


NBS BIM Object Standard

This BIM object has been authored to meet the requirements of the NBS BIM Object Standard.

Find out more about the NBS BIM Object Standard.

Platform Compatible Version




Revit 2017


Third party certifications

Carbon Footprint Standard

Carbon Footprint Standard

ABG Roofdrain 25mm Drainage Geocomposite - Embodied Carbon Certificate




Case studies

ABG blueroof - Green Biodiverse, Moreland Primary School, Islington, UK

ABG blueroof - Green Biodiverse, Moreland Primary School, Islington, UK

ABG blueroof - Green Extensive, Huddersfield University, UK

ABG blueroof - Green Extensive, Huddersfield University, UK

Green Roof Extensive, Leeds Skelton Lake Services, UK

Green Roof Extensive, Leeds Skelton Lake Services, UK

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