Excavated earth and fill materials

Free draining subsoil.

Bioretention soild for use within Sustainable Drainage Systems (SuDS).

Intensive lightweight washed sand subsoil.

SuDS sand subsoil.

Intensive lightweight subsoil.

Extensive Substrate (A20703/1) is a lightweight, well-draining growing medium designed for green roof applications. It has a high total porosity of 54.2%, ensuring effective moisture retention and aeration while preventing waterlogging.The bulk density ranges from 0.88 g/cc when oven-dried to 1.25 g/cc at field capacity, indicating a lightweight structure that reduces roof load. Its saturated hydraulic conductivity of 18.1 mm/min supports efficient drainage, while a field capacity of 36.8% ensures water availability for plant growth. The pH of 8.1 is slightly alkaline, making it suitable for drought-tolerant vegetation.With a C:N ratio of 8.10 and adequate macronutrient levels of phosphorus and potassium, this substrate provides a stable and nutrient-balanced environment for extensive green roofs.Stones (>8 mm): 61.8%.

BS 8601 Subsoil.

Washed sand subsoil.

BS8601 free-draining subsoil with a sand content of 95%.