FREQUENTLY ASKED QUESTIONS

Frequently asked questions

How much does it cost to install a green roof and are funding options available?


The average cost to install a green roof ranges from $10 to $12.50/sqft for an extensive (Sedum) green roof and $16 to $20/sqft for more intensive green roofs. If the green roof is integrated into the design in the beginning of the construction, the costs per square foot decreases.




What is the difference between an intensive and extensive green roof?


Extensive Roof

  • Shallow growing medium (soil) between 2 and 6 inches
  • Less structural support
  • Limited plant diversity with less intricate root systems
  • Less investment and little maintenance once established
  • Requires minimal maintenance after the first year
  • For roofs without occupancy or capacity for gathering
Intensive Roof
  • 6+ inches or deeper growing medium (soil)
  • More structural support as growing medium to support heavier plants
  • Can support a larger variety of plants and trees
  • Can support raised beds
  • Higher initial investment and more intensive maintenance
  • May require an irrigation system
  • May be accessible for residents to socialize, with appropriate access and Certificate of Occupancy




Can I install a green roof myself or should I hire a professional?


In NYC, it is advised to connect with a professional design-build firm consultant who can guide you through the design process, assist with procuring funding and permits, and safely install and maintain your green roof. Scroll below to see design-build firm examples.




What time of year is best to install a green roof in NYC?


Spring. Planting in high summer will require extra irrigation and autumn may not allow enough time for the plants to get established before winter. Some plants can be installed while dormant in the winter.




How long does it take to install a green roof?


Residential projects can be installed within a few days. Commercial installations can take up to two weeks due to generally larger roof sizes. Allow time for permitting and filing processes that may apply to your project.




How long does it take for plants to be established on green roofs?


It can take plants a minimum of three years to establish on green roofs.




Do all green roofs need irrigation?


Extensive green roofs may not require irrigation because most suitable plants are drought-tolerant. Depending on the plants selected, intensive roofs may require drip irrigation.