A green roof or living roof is a roof of a building that is partially or completely covered with vegetation and a growing medium, planted over a waterproofing membrane.

Green roofs serve several purposes for a building, such as absorbing rainwater, providing insulation, creating a habitat for wildlife, and decreasing stress of the people around the roof by providing a more aesthetically pleasing landscape, and helping to lower urban air temperatures and mitigate the heat island effect.

It may also include additional layers such as a root barrier and drainage and irrigation systems. Container gardens on roofs, where plants are maintained in pots, are not generally considered to be true green roofs, although this is debated. Rooftop ponds are another form of green roofs which are used to treat greywater. Vegetation, soil, drainage layer, roof barrier and irrigation system constitute green roof. They effectively utilize the natural functions of plants to filter water and treat air in urban and suburban landscapes.

Green roofs are suitable for retrofit or redevelopment projects as well as new buildings and can be installed on small garages or larger industrial, commercial and municipal buildings.


Green roofs can improve the energy performance of buildings, help manage stormwater, reduce airborne emissions, and mitigate the effects of urban heat islands.

The greater insulation offered by green roofs can reduce the amount of energy needed to moderate the temperature of a building, as roofs are the area of the greatest heat loss in the winter and attain the hottest temperatures in the summer.


A green roof is part of an effective strategy for beautifying the built environment and increasing investment opportunity of NYC.

The temperature moderating effects of green roofs can reduce demand on power plants, decreasing CO2 and other polluting by-products.

Green roof plants capture airborne pollutants and atmospheric deposition, and can also filter noxious gases.


Commercial and industrial roofs no longer need to be eyesores of endless concrete, asphalt or gravel. A green roof alleviates the harsh, stark and ugly views. Green roofs also assist in dampening noise. The multifaceted surfaces of plants and porous nature of the material help to both deflect and absorb noise not only of the city but can also assist in dampening sounds from rooftop mechanical equipment.

Endless Design Possibilities

Green roofs offers endless design possibilities, limited only by its function and the slope of the roof. Natural views create more productive, healthy, happy, creative and relaxed people. Plants and soil help create new habitats for butterflies, insects and birds.


The U.S. Environmental Protection Agency (EPA) encourages the creation of green roofs for mitigating the urban “heat island effect,” whereby temperatures in crowded cities can soar some 10 degrees Fahrenheit higher than in less developed areas nearby.

Another benefit from a green roof is its ability to filter pollutants like carbon dioxide out of the air and heavy metals out of rainwater. Green roofs also help reduce building heating and cooling costs due to the buffering effect of the plant matter and soil. Other benefits, says the EPA, include providing a yard or patio for tenants to enjoy year ’round.


Most waterproof roofing systems break down and begin to fail due to exposure to UV rays and significant temperature swings that expand and contract materials leading to seam failure.

Green roof installations protect the roofing materials from direct UV exposure, reduce environmental wear and tear and increase the roof’s life span. Some roofing manufacturers are beginning to recognize this benefit and are offering longer warranties.


Biodiversity is the number, variety, and variation of different organisms found within a specific geographic region. A bio-diverse environment can have both native and introduced species. The key word in a bio-diverse environment is “diversity”. For an environment to thrive there must be competition and a prey-predator relationships to strengthen the key players within that ecology.

Creating biodiversity on a green roof is significantly different from restoring it on ground level. On a rooftop there is no pre-existing ecology to enhance. Everything is from scratch.

Beside accessibility, high winds, temperature extremes and proximity to the sun can also be very challenging issues for organisms.
Studies show that plant selection and depth of growing media have the greatest influence on the biodiversity of a green roof.


Most buildings are designed to shed rain and are built with hard, impenetrable roofing surfaces. As a result, rainwater bounces off and collects as runoff, picking up impurities including infectious bacteria from animal waste as well as harmful pesticides and fertilizers, on their way to municipal storm sewers. Eventually, this (and everything!) empties into our local bodies of water.

Conserve Water

Minimizing runoff means that more impurities will remain in local soils where they can be broken down more easily into their constituent elements than if they are concentrated downstream.
To achieve this goal, green roofs use living plant matter and soil on top of a building to absorb, collect and reuse rainwater while preventing runoff.
Many buildings employing green roofs are able to find abundant uses for the water they collect, from watering exterior plants at ground level to flushing toilets


The Green Roof Property Tax Abatement provides a one-year tax abatement for the construction of a green roof on residential and commercial buildings in New York City. The green roof tax abatement is aligned with the City’s long-term sustainability plan, PlaNYC.

Green Roof Property Tax Abatement

In general, a green roof is an addition to a roof that includes, among other things, a growth medium and a vegetation layer of drought-resistant and hardy plants. Green roofs help improve storm water management, provide insulation for the building, and lessen the urban heat island effect, which causes dense urban environments to have higher temperatures than other areas.

Rooftop Gardens