Icopal Extensive Sedum Substrate is the ideal green roof growing medium for sedum species

Icopal Sedum Substrate - For Extensive Green Roofs

Sedum species lend themselves very well to their use within extensive green roof systems. They are very drought tolerant, but do not thrive when the root zone is constantly wet. Therefore the Icopal Extensive Sedum Substrate is the ideal growing medium for sedum species, as it is able to hold sufficient water to enable healthy growth, yet it is free-draining.


The Icopal Sedum Substrate is a lightweight, free draining, low nutrient and moisture retentive growing medium made from 70% recycled material in line with the UK Green Roof Code of best practice.  It is a specially blended mix of free draining organic material with clean, screened granular aggregates, recycled from certifiable waste products from the building industry, to provide a low nutrient water retentive growing medium. In compliance with soil association standards and certifications.


Product Code Description Size
3101077 Icopal Sedum Substrate 1.25 m3 (IBC)
3101078 Icopal Sedum Substrate 25 kg (bag)



Composition: Recycled crushed brick and Organic material (Green Waste)
Weight/Unit Volume (dry): 870 kg·m-3
Weight/Unit Vol. (saturated): 1240 kg·m-3
Compaction: 10%
Water Retention: 25%
Availability: 1.25m3 IBC bulk bag; 25 kg sack


Icopal Sedum Substrate is for use in conjunction with the relevant specified components of the associated Icopal extensive roof system. It may be used on both flat roofs with minimum fall of 1:60, and when properly specified, on sloping roofs up to 10 degrees. For slopes greater than 10 degrees, advice relating to retaining the system should be sought from Icopal’s Technical Department.

The roof deck should have sufficient drainage points to quickly drain away water to prevent ponding and substrate saturation.


Icopal Sedum Substrate should be installed onto an appropriate Icopal Drainage Board and filter layer to ensure the substrate remains free-draining to avoid saturation of the substrate.

Installation Details

The Icopal Sedum Substrate should be laid to a minimum recommended settled depth of 50 mm. The Icopal Sedum Substrate is poured onto the filter fleece/drainage layer and raked, allowing for settlement, to the depths required. The Icopal Sedum Substrate should not be installed when the substrate is saturated.

The Icopal Edge Restraint detail can be used to retain the sedum system; including the growing substrate.

It is recommended that gravel borders are used to keep the planting away from any waterproofed upstands, and around roof equipment or structural openings/penetrations such as rooflights etc. The width of the border should be a minimum 300 mm, in accordance with GRO recommendations. The use of borders can also provide roof maintenance access, as extensive green roofs are not intended to support foot traffic.

Sedum seed mixes may be sown over the top of the installed substrate. Plug plants or pre-grown planting mats may also be installed

Typical Specification

The Icopal Sedum Substrate is laid to a level, minimum settled depth of 50 mm, and above the relevant Icopal Drainage Board and filter layer. Icopal Sedum Substrate should be laid in accordance with Icopal’s instructions, and used in conjunction with other relevant specified Icopal components.


The Icopal Sedum Substrate is delivered in 1.25 cubic metre IBC bulk bags. The bags are generally lifted onto the roof by crane and the substrate poured onto the roof, where it is then raked level to the required depth. The substrate can also be delivered in bulk tippers or 25 litre bags as logistics demand and allow.

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