Living Roofs

photo of living roof

Picture of the Ritz Carrolton in Charlotte

GreenStar is committed to bringing the best engineered and designed living roofs for your commercial and business properties in New Orleans and surrounding areas.

A recent report commissioned by the Office of Federal High Performance Green Buildings includes a literature review of 200 research studies, in-depth analysis of green roof benefits, an original cost-benefit analysis, discussion of challenges and best practices.

Benefits of a Living Roof

  • Stormwater Management: Most urban and suburban areas contain large amounts of paved or constructed surfaces which prevent stormwater from being absorbed into the ground. The resulting excess runoff damages water quality by sweeping pollutants into water bodies. Green roofs can reduce the flow of stormwater from a roof by up to 65% and delay the flow rate by up to three hours.
  • Energy: Green roofs reduce building energy use by cooling roofs and providing shading, thermal mass and insulation.
  • Biodiversity and Habitat: Green roofs provide new urban habitat for plants and animals, like birds and insects, thereby increasing biodiversity.
  • Urban Heat Islands: Cities are generally warmer than other areas, as concrete and asphalt absorb solar radiation, leading to increased energy consumption, heat-related illness and death, and air pollution. Green roofs can help reduce this effect.
  • Roof Longevity: Green roofs are expected to last twice as long as conventional roofs
  • Aesthetics: Green roofs can add beauty and value to buildings.

Cost Benefit

  1. GSA’s green roof report estimated that green roofs on commercial and public buildings provide a payback, based on 50 year average annual savings, of about 6.2 years nationally, internal rate of return of 5.2%, and an ROI of 224%, based on a net present value of $2.7/square foot.
  2. Primary green roof costs are related to installation and maintenance.
  3. Primary economic benefits of installing green roofs are lower energy costs, less frequent roof replacement due to greater durability, reduced stormwater management costs, and creation of job opportunities.

GreenStar will perform best practice application analysis:

  • Ensuring a building can structurally support a green roof
  • Quality installation and leak prevention
  • Maintenance requirements to avoid plant loss and other problems
  • Installing green roofs on historic buildings

GreenStar Roofs Product Contribution

GreenStar Roofs contribute to LEED certification through a series of credits which builds in varying degrees through its official rating system. This means that though all green, living roofs are different, they can still earn credits by following a few simple guidelines.

The guidelines of credits and their associated points are as follows:

SS Credit 5.1 – Site Development – Protect or Restore Habitat (1 point)

  • Projects earning SSc2 (Development Density and Community Connectivity) may include vegetated roof surface in this calculation if the plants are native or adapted, provide habitat, and promote biodiversity.
  • Once established, native/adapted plants require minimal or no irrigation; do not require active maintenance such as mowing or chemical inputs such as fertilizers, pesticides or herbicides; and provide habitat value and promote biodiversity through avoidance of monoculture plantings.

SS Credit 5.2 – Site Development – Maximize Open Space (1 point)

  • Projects in urban areas earning SS credit 2, vegetated roofs can contribute to credit compliance

SS Credit 6.1 – Storm Water Design: Quantity Control (1 point)

  • Specify vegetated roofs, pervious paving and other measures to minimize impervious surfaces.

SS Credit 6.2 – Storm Water Design: Quality Control (1 point)

  • Use alternative surfaces (e.g., vegetated roofs, pervious pavement, grid pavers) and nonstructural techniques (e.g., rain gardens, vegetated swales, disconnection of imperviousness, rainwater recycling) to reduce imperviousness and promote infiltration and thereby reduce pollutant loadings.

SS Credit 7.2 – Heat Island Effect: Roof (1 point)

  • Install a vegetated roof for at least 50% of the roof or Install high albedo and vegetated roof in combination (Area of SRI roof/0.75) + (Area of Veg Roof/0.50) ≥ Total Roof Area
  • Exemplary Performance Credit – Vegetate 100% (less mechanicals, pv, skylight, etc.) of the roof (ID Credit 1.1 – 1 point)photo of credentials

Credits Where GreenStar Roofs Play a Supporting Role

Water Efficiency

WE Credit 1 -Water Efficient Landscaping (Potential: 2-4 Points)

  • If this credit is pursued, be sure to design the green roof system without permanent irrigation, or if irrigation is necessary, minimize potable consumption with drip irrigation and/or irrigation with reclaimed water.
  • Option 1: 2 points for reducing potable water for irrigation by 50%
  • Option 2: 4 points for no potable water use for irrigation. Temporary irrigation systems for plant establishment acceptable if removed within 1 year to 18 months of installation.
  • If the percent reduction of potable water is 100% AND the percent reduction of total water is equal to or greater than 50%, both Option 1 and Option 2 are earned.

Energy and Optimization

EA Credit 1 – Optimize Energy Performance (Potential: Up to 19 Points)

  • Vegetated roofs can aid in the reduction of the energy demand for the project. Demonstrate a percentage improvement in the proposed building performance rating compared with the baseline building performance rating.

Credits Where GreenStar Provides Additional Impact

Materials and Resources

MR Credit 3 – Material Reuse (Potential: 1-2 Points)

  • Reuse building materials and products to reduce demand for virgin materials and reduce waste, thereby lessening impacts associated with the extraction and processing of virgin resources.
  • The sum of reused materials must constitute at least 5% or 10%, based on cost, of the total value of materials on the project.

MR 4 – Recycled Content (Potential: 1-2 points)

  • Modules, pavers, edge treatments, and growth media components (compost) are from both pre-consumer and post-consumer materials
  • Contributes towards having 10% to 20% of the total value of project materials originating from recycled material
  • Potential 1 to 2 points (10% or 20%, respectively), depending on the overall percent of project recycled materials

MR 5.1 – Regional Material (Potential: 1-2 points)

  • 10% or 20% of product, depending on the overall percent of materials extracted, must be manufactured and assembled within 500 miles.

Summary

Overall, the GreenStar Green Roof system installed on 50% or more of the roof surface virtually guarantees 2 LEED® points and can contribute an additional 7+ points toward LEED® certification, almost 20% of the total needed to certify.

Based on USGBC LEED ® for New Construction Version 3 (2009)