• Why to use composite materials for drainage layers, and not aggregates?

- Diadem composite drainage boards have much greater drainage and storm water retention capacity than aggregates.
- Also, Diadem drainage and retention boards are made from recycled materials while aggregates are typically mined from nature. Mining materials may have a significant negative impact on the environment.
- Aggregates are heavier than composite drainage boards, and may increase roof loads and structural requirements.
- Multiple trucks and/or shipments may be required to deliver the quantity of aggregate required for a project, causing potential jobsite logistical issues.

• Should boards be installed with diffusion holes up or down?

Boards are typically installed with diffusion holes up as this maximizes their storm water flow delay and retention characteristics. When boards are installed with diffusion holes down, storm water is not retained and immediately drains away. "Holes down" is the appropriate technique for installing boards beneath pavers, decking, or hardscape.

• Why are drainage and retention boards with double-shaped sides superior to others?

Double-sided boards allow two levels of ventilation and drainage, enhancing horticultural conditions and plant performance, while still allowing water to freely drain from the roof.

• Why is Polystyrene the material used?

Polystyrene retains its shape in high summer temperatures, and data supports that even after 50 years it will not substantially change form. Polystyrene is also commonly available as a post consumer recycled material, making it a more sustainable product.