Roofing Membrane Can be fluid (like hot rubberized asphalt, BUR) or single ply; EPDM, PVC, TPO or modified bitumen.
Insulation Typically extruded polystyrene. NOTE: insulation goes beneath a fluid membrane application and above a single ply membrane.
Drainage System A light-weight board with long-term stability and a filter fabric that allows water to pass through it will preventing fine soil to pass through it.
Moisture Retention Mat This prevents storm water runoff by evening the flow of water of the roofing system.
Root Barrier This protects the roofing system from vegetative root penetration.
Soil or Engineered Planting Media with these characteristics.
Resists decomposition
Excellent aeration
Water holding capacity
Drainage
Bulk density
Plant support
Nutrient supply
Doesn’t clog filtration system
Vegetation
Depending on the intensive or extensive nature of the green roof.
Vegetation
Sedum
Sedum is a plant genus representing about 400-600 species of leaf succulents, found throughout the northern hemisphere, varying from annual groundcovers to shrubs. The plants have water-storing leaves. Many sedums are extensively cultivated as garden plants, due to their interesting and attractive appearance and hardiness. The various species differ in their requirements; some are cold-hardy but do not tolerate heat, some require heat but do not tolerate cold. They are preferred to grass for green roofs.
500 different varieties
Very resilient
Drought tolerant
Sedum species for various areas of the country
Grown in separate blocks, suppliers don’t mix cells.
Shipped in flats (i.e., 24 – 3” plugs to a flat or 72 – 1” plugs to a flat-- Some roofs are planted from plugs propagated off site.) Green Grid Trays, the latest development, can be designed to go directly to the roof membrane
Trimming can be used to “seed” the media
Factors Affecting the Hardiness of a Green Roof
Heat radiating from building warms the root
Soil depth
Roof orientation
Moisture level in soil
Wind
Reflected light/heat
How well established the roof is
Warranties
Marshall only installs green roof systems that are fully warranteed.
