A green roof is a roof covered with living vegetation over a waterproof membrane. Depending on depth and design, it can reduce stormwater runoff, provide insulation, and support wildlife. This guide explains the main types and what to consider.
Types of Green Roofs
- Extensive: shallow soil (often a few inches), low-growing plants such as sedums, and light weight. Lower maintenance.
- Intensive: deeper soil that supports shrubs, lawns, or gardens. Heavier and needs more maintenance.
Benefits
- Reduces stormwater runoff by holding and slowly releasing rainwater
- Adds insulation, which can reduce heating and cooling loads
- Provides habitat for pollinators and birds
Considerations
- Structure: the roof must be designed to carry the added weight when saturated.
- Waterproofing: membranes must be durable and protected from roots.
- Installation: installation usually requires specialized contractors and permits.
- Cost: installation is often more expensive than a conventional roof.
Get Professional Advice
Consult a structural engineer and an experienced green roof installer before committing. Ask for references from completed projects.
