Green Roofing: Is a Living Roof Right for You?

Green roofs — also called living roofs — incorporate a growing medium and vegetation on top of a waterproof membrane. They're growing in popularity for both commercial and domestic applications as sustainability becomes a higher priority.

Types of Green Roof

• Sedum/extensive green roof: thin growing medium (50–150mm), low-maintenance drought-tolerant plants, lightweight, suitable for most flat roofs
• Semi-intensive: medium depth, wider plant variety including grasses and herbs
• Intensive (roof garden): deep growing medium (150mm+), suitable for trees and shrubs, requires structural support

Benefits of Green Roofs

• Extends the life of the waterproof membrane by protecting it from UV and temperature extremes
• Improves insulation and reduces heating and cooling costs
• Reduces surface water runoff
• Increases biodiversity — provides habitat for insects and birds
• Improves air quality and reduces urban heat island effect
• Attractive appearance — green space in urban environments

Structural Considerations

Before installing a green roof, the structure must be assessed to ensure it can carry the additional load. An extensive sedum roof adds around 60–150kg/m² when saturated. A structural engineer should confirm the existing structure is adequate.

Maintenance

Extensive sedum roofs require minimal maintenance — usually just an annual visit to remove weeds and check the drainage layer. More intensive systems require more regular attention.