Type V


CSI Specification: Type V (DOCX) --------------------
CSI Specification: Type V (PDF)

A synthetic reservoir sheet over a protection fabric forms the base of the Type V assembly, which offers one solution to installing a three-course green roof over a PMR roofing system. A deep reservoir sheet is required; typical reservoir sheets are 2.6 to 2.4 inches (4 to 6 cm) thick and usually retain between 0.2 and 0.4 inches (0.5 to 1.0 cm) of water when filled with granular media. The coarse, large-grained granular media in the reservoir sheet cups 1) stabilizes the sheet, 2) facilitates drainage, and 3) reduces the potential for drought stress. A root-permeable separation fabric separates the fine-grained growth media from the granular media and prevents the fines from mixing with the granular media. The reservoir sheet stores captured rain or irrigation water for the root mass, and irrigation is provided by surface or sub-surface (just above the reservoir sheet) drip lines. Typical assembly thicknesses range from 6 to 10 inches (15 to 26 cm).

Typical Type V profile:

  • wind erosion stabilization system
  • growth medium
  • root-permeable separation fabric
  • light-weight granular drainage media
  • synthetic reservoir sheet (water storage layer)
  • protection fabric
  • root barrier membrane (when required)
  • waterproofing system

Data Sheet

Type V Data Sheet

Case Studies

Queens Botanical Garden, Flushing, NY