Why Green Roofs?

Compared with other emerging green technologies that offer singular benefits, the installation of a green roof affords cost-saving and environmental benefits in many areas.

Add Financial Value: Green Roofs Directly Save You Money

Extend Service Life of the Roof 2-3x

Applying a green roof to your roof surface protects the waterproofing membrane from UV radiation. Therefore the life of your waterproofing membrane is extended three to four times its average life, meaning that, in the long run, you save money and fewer materials go into the landfill because it does not need to be replaced as frequently. Green roofs also protect the roof surface from human traffic, dust and other debris.

Green Roofs Extend Roof Life

Manage / Absorb Stormwater Runoff

Green roofs are a best practice for onsite water management. Here's why: They can reduce the storm water runoff volume to sewer systems by 50 - 90% and peak storm water runoff flow by 75%-90%.* By comparison, a typical roof will retain 10% of storm water runoff.

Why should I care? Hundreds of communities in the United States have combined sewer systems. During heavy rainfalls excess water and the water contaminants associated can lead to combined sewer overflows into our watersheds. Green roofs present an opportunity to mitigate this all-too-common problem by absorbing much of the water in the root systems and releasing the rest back into the atmosphere through evapotranspiration. If there is runoff, green roofs slow it so that the sewer system isn't overburdened during peak usage.

Most commercial spaces are required to retain stormwater on site. A green roof eliminates or greatly decreases the space needed and costs associated with dealing with the stormwater.

View a study on storm water retention conducted in the city of Boston which demonstrates a 64% storm water retention rate in a green roof study conducted over a 10 year period.

Ford's Rouge Plant, at over 450,000 square feet, is the largest green roof in the United States and saved over $10 million on the installation of a storm water runoof treatment system.**

* Penn State University Green Roof Research
** Apex was not involved in the Ford green roof installation

Reduce Energy Costs / Increase Insulation

Installation of a green roof can greatly improve the insulation qualities of a roof, reducing heat flow as much as 70-90% in a warm climate and 10-30% in a cold climate.* Green roofs greatly reduce the temperature of your roof in the summer time. It works best in buffering against daily temperature extremes. Your roof regularly reaches temperatures of 160º F. With a green roof the temperatures stay closer to 80º F. This means in the summer when energy demands and their associated costs are the highest you are reducing the amount of energy your building requires. The same is true in the winter but to a lesser degree. In today's world of rising energy costs, green roofs provide an amazing benefit.

* Penn State University Green Roof Research

Reduce Heat Island Effect

A natural function of plants is to cool the air through evapotranspiration (or release of water through plants into the atmosphere). With an increase of green roofs in the urban fabric we will start to see a reduction of the overall heat trapped in our cities.

Improve Air Quality

Like all plants, green roof plants sequester carbon dioxide from the air and release oxygen. Additionally, they remove smaller amounts of other contaminants in the air. Installation of a green roof can mitigate a significant amount of C02 emissions. A 10,000 square foot extensive system will capture over 800 pounds of C02 annually.*

Green roofs also naturally filter harmful particulates and air pollutants.

* Michigan State University Green Roof Research

Higher Property Value & Quality of Life

Although difficult to quantify, green roofs provide many auxiliary benefits. Green roofs:

  • Introduce an attractive and a dramatic amenity and transform rooftop eyesores into assets.
  • Reclaim space for relaxation and passive recreation for employees and residents.
  • Increase productivity for employees and recovery time for patients in health care facilities.
  • Reduce noise heard by occupants, particularly near highways and airports.
  • Create green space in neighborhoods that have little ground level space, increasing livability and helping to meet municipal mandates for green space.
  • Create marketing value for your building and organization, resulting in higher rents and increased resale value.

A recent study by UMass Boston estimates that green roofs can increase property value by an average of 15%.

Create Wildlife Habitats

Although green roofs cannot replace a habitat destroyed by development, through thoughtful plant selection, green roofs create new wildlife habitats for pollinators, birds, insects, and even small animals.

Earn LEED Credits

Green roofs can earn LEED credits in the following categories of the USGBC's green building rating system:


  • Reduced Site Disturbance, Protect or Restore Open Space
  • Reduced Site Disturbance, Development Footprint Credit
  • Landscape Design That Reduces Urban Heat Islands


  • Storm Water Management
  • Water Efficient Landscaping 
  • Water Use Reduction 
  • Innovative Wastewater Technologies 


  • Optimize Energy Performance
  • Renewable Energy 
  • CFC and Ozone Depleting Substance Reduction


  • Storage and Collection of Recyclables
  • Recycled content materials



Learn more about LEED credits for green roof systems:


Increase the Efficiency of Solar Panels

Solar panels operate most efficiently at 80° F. In general, a standard roof surface can reach temperatures of 160°-180° during the summer season. A green roof will lower the ambient temperature to 80° even on the hottest days, therefore making the solar panels work more efficiently (an increased efficiency of 8%). This is why green roof systems and solar energy panels make for a great energy saving solution when used in combination.