FAQ

There are 3 types of green roofs.

1. Extensive green roofs

Characteristics: Lightweight, with a thin growing medium (4-6 inches), requiring minimal maintenance.
Plants: Drought-tolerant plants like sedum, mosses, and herbs.
Application: Suitable for roofs with limited load capacity, such as residential or commercial buildings.
Maintenance: Occasional weeding, annual inspections, and maintenance of drainage systems.

2. Intensive green roofs

Characteristics: Heavier, with a deeper growing medium (up to 12 inches or more). Functions like a rooftop garden.
Plants: A wide range, including grasses, flowers, shrubs, and even small trees.
Application: Ideal for buildings with strong structural support, such as commercial complexes and public spaces.
Maintenance: Requires regular gardening tasks, including pruning, watering, and fertilizing.

3. Semi-intensive green roofs

Characteristics: A hybrid combining elements of both extensive and intensive green roofs.
Plants: A mixture of grasses, flowering plants, and low-maintenance shrubs.
Application: Suitable for buildings wanting a mix of low-maintenance greenery and decorative landscaping.
Maintenance: Moderate maintenance depending on plant selection.

Environmental Benefits:

• Climate Regulation: Green roofs reduce the “urban heat island” effect by absorbing sunlight and cooling the surrounding air.
• Air Quality Improvement: Plants filter pollutants and dust particles from the air.
• Rainwater Management: They retain rainwater, reducing runoff and preventing urban flooding.

Economic Benefits:

• Energy Savings: Improved insulation leads to reduced heating and cooling costs.
• Extended Roof Lifespan: The layers of a green roof protect the roof membrane from harsh weather, UV radiation, and mechanical damage, prolonging its life by up to 50 years.
• Increased Property Value: Green roofs enhance a building’s appearance and sustainability rating, boosting market value.

Social Benefits:

• Urban Biodiversity: They create habitats for birds, insects, and pollinators.
• Aesthetic Appeal: Green roofs transform urban landscapes into beautiful, nature-inspired environments.
• Improved Well-Being: Access to green spaces has been shown to reduce stress and promote mental health.

The cost of a green roof depends on several factors, including the type of green roof, size, structural requirements, plant selection, and labor costs.

• Extensive green roofs: Typically cost between $50 – $80 per square foot due to their lighter and simpler structure.
• Intensive green roofs: Can range from $80 – $150+ per square foot due to the additional structural support, soil depth, and plant diversity required.

Additionally, maintenance costs should be factored in, especially for intensive green roofs, which may require professional landscaping services.

Maintenance needs vary depending on the type of green roof:

• Extensive roofs: Require minimal maintenance. Inspections should be conducted at least twice a year to check for drainage blockages, weeds, and roof membrane integrity.
• Intensive roofs: Need regular gardening tasks such as watering, pruning, fertilizing, and replacing dead plants.
• Common tasks:
  • Weeding unwanted plants
  • Inspecting the drainage system
  • Removing debris and litter
  • Monitoring plant health and growth

Yes, green roofs can be adapted to different climates with proper design and plant selection:

• Hot and dry climates: Use drought-tolerant plants like succulents and cacti.
• Cold and snowy climates: Choose hardy plants that can survive frost and snow.
• Rainy and humid climates: Consider moisture-loving plants and ensure an efficient drainage system.

Design considerations, such as the type of growing medium and irrigation systems, play a crucial role in ensuring the roof’s success in various climates.

• Extensive Green Roofs: Typically do not need regular irrigation after establishment, as they rely on natural rainfall.
• Intensive Green Roofs: Often require irrigation systems due to a greater variety of plants with different water needs.

Drip irrigation systems are commonly used, as they deliver water directly to plant roots, minimizing waste. Smart irrigation controllers can further optimize water use.

With proper maintenance, green roofs can last 40-50 years or even longer. The longevity depends on factors such as:

• Quality of installation and materials
• Proper drainage and waterproofing
• Regular maintenance and inspections
• Suitable plant selection for the climate

By protecting the underlying roof structure from weather extremes, green roofs significantly extend the lifespan of conventional roofs.