Expanded Clay Aggregate (ECA) is an ideal substrate for green roofs and roof gardens. Using a combination of ECA pebbles and soil is a great option for those looking to construct more eco-friendly buildings.
This is because ECA is much lighter, by volume than soil. When a large amount of soil is present on a roof, a high load may be transmitted to the rest of the building, which it may not be able to support. Using ECA keeps the static load low, enabling green roofs to be built even on structures with lighter-weight construction. And because ECA has a neutral pH, it has a minimal effect on the surrounding soil and plants.