Jan 08 2026
Green Roof Edge Design for Drainage and System Retention
Green Roof Edge

Understanding Green Roof Edge Conditions

Did you know that when designing a green roof, drainage at edge conditions must be carefully considered? A green roof edge plays a critical role in retaining the green roof system while allowing excess water to drain properly from the roof assembly.

 

Roof penetrations and roof edges must be evaluated together when selecting the components needed for a complete green roof system.

Drainage and Retention at Green Roof Edges

Green roof edge details must be carefully designed to both retain the green roof layers and allow for proper drainage of water. Without adequate drainage openings, water can accumulate at the perimeter and compromise system performance.

 

Edge detailing must work in coordination with the roof drainage strategy to support long-term durability.

Typical Configuration

Green roof edges are typically bent at 90 degrees. The bottom horizontal leg may fasten to or rest on the roof deck depending on project requirements.

 

The vertical leg includes drainage opening slots, usually starting at the bend location. The overall height of the green roof edge depends on project-specific conditions, including green roof depth and drainage requirements.

 

Material Options for Green Roof Edges

 A wide range of materials are available, including:

 

  • Stainless steel

  • Copper

  • Powder-coated aluminum

  • Corten steel

  • PVC

 

Product lengths and heights vary to accommodate different green roof system depths and design needs. Selecting the right material helps balance durability, aesthetics, and compatibility with the overall roof system.

Key takeaways

Design TOgether with your product manufacturer or Green Roofing Consultant to select the appropriate green roof system and green roof edge detail for your project. Proper coordination ensures edge conditions support drainage, system retention, and long-term roof performance.

 

In summary, well-designed green roof edge detailing is essential to managing water at the perimeter while maintaining the integrity of the green roof assembly.

Ready to streamline Green Roof Edge detailing into your design? 

Discover how D.TO enhances your daily design workflows on D.TO’s key features page, or schedule a demo to explore them in more detail!!

Written by D.TO: Design TOgether

Empower your daily practice