Design and Development of a Roof Garden
- Design Parameters -
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The Basic Green Roof Garden
A green roof is a green space created by adding layers of plants on top of a traditional roofing system. The layers of a contemporary green roof system, from the top down, include:

• The plants, often specially selected for particular applications
• an integrated irrigation system and controls
• an engineered growing medium, which generally will not include soil,
• a landscape or filter cloth to contain the roots and the growing medium, while allowing for water penetration,
• a specialized drainage layer, sometimes with built-in water reservoirs,
• the waterproofing/roofing membrane, with an integral root repellent, and
• the roof structure, with traditional insulation either above or below.

Design Considerations
There are several important design and structural differences between ground level landscape development and rooftop developments. The following are the special construction requirements and considerations when developing a roof garden.

• Protection of the integrity of the roof and structure
• Positive drainage
• A long-term, lightweight planting medium
• Irrigation for optimum plant growth and sustainability
• Adaptation to the climatic conditions
• Selection of hardscape materials (paving, structural materials, site
  furnishings and water as a design element) and their special use and
  requirements as part of a roof garden system
• Provisions for utilities
• Public safety and security
• Ease of maintenance