Green Roof Necessities

Green roofs are becoming increasing popular in all area of the world, acting not only with eco-function, but to beautify areas that may not have access to plantings. There are several green roof necessities required for a successful garden, but the overall project does not have to be complicated.

Requirements for a Green Roof Garden

The first step in creating a green roof is evaluating the roof itself. Flat roofs work the best, but a sloped roof will also do. Some roofs may need reinforcement prior to starting. There are two types of green roof gardens: Intensive and Extensive.

Intensive roof garden necessities are a base of soil 12” deep, which will provide an excellent foundation for a variety of plants. Intensive gardens are named such as they require more attention as the plants are larger, and may need more irrigation, feeding and maintenance. 

Extensive gardens are the opposite, and can be created using 3”of soil and are self sustaining once established. Often lower ground covers, mosses and sedum are used for their resistance to the elements.

Other necessities for a green roof include the following.

• A waterproof membrane to prevent leakage within the building. 
• A root barrier to prevent root growth from infiltrating the roofing system and compromising the water proof barriers. 
• A drainage layer is needed to prevent any over saturation of the growing medium, as well as relieve the roof of excess weight. 
• Filter mats hold the growing medium in place in order to prevent wash outs and drainage clogs.
• Growing mediums are the engineered substance that provides the base and necessary nutrients for the plants. This substance also absorbs and drains water more efficiently, and is created especially for roof gardens.
• Another possible roof garden necessity is an irrigation system, at least until some of the plantings take hold. Intensive roof gardens need a system that is regular.

Plants for a Green Roof

• Various species of sedum and Talinum. These are succulents that perform well in dry conditions.
• Grasses such as Andropogon, Carex, or Sporoblus. Many of these are wind resistant.
• Herbaceous Perennials – Phlox, Petrorhagiz. These sturdy plants come back year after year.
• Flowering perennials that attract butterflies and hummingbird.
• Various species of low growing evergreens.

Green Roof Necessities for Plants

• rapid growth and continual spreading without airborne seeding
• ability to tolerate droughts and high wind
• low growth height
• low maintenance requirements for trimming, weeding, or feeding
• shallow, fibrous root systems
• no or low specific irrigation and nutritional needs

A roof garden is a rewarding, eco-conscious effort that is enjoyed by many. They are not just for commercial use – residential buildings are adding them for their green effect socially in areas dominated by concrete and pavement. The overall benefits are immense, ranging from heat reduction and storm water run-off reduction, as well as filtering pollutants and creating sound barriers. A roof garden is an excellent eco-friendly choice.