855773644-LEED-v5-BD-C-Reference-Guide-Launch-Edition - Page 156

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Option 1. Nonroof and Roof

Implementing both nonroof and roof measures are essential in mitigating heat island effects, with each providing significant environmental benefits to the building, site, and occupants. Using a combination of nonroof and roof strategies can create a more sustainable and resilient urban environment.

Nonroof measures Nonroof measures include shading with new or existing plant material or shading structures, specifying high reflectance paving and open-grid paving, and including vegetated planters across the site. Using a variety of plant species allows for biodiversity, while tree canopies and shading structures create areas of respite on a hot, sunny day.

Roof measures Roof measures, including the use of vegetated and high reflectance roofs, can improve energy efficiency and thermal comfort and can reduce carbon emissions associated with building energy use.

Projects pursuing this option must consider the slope of the roof, and both the initial and aged SRI value when selecting compliant materials. For low-sloped roofs, the roofing material must meet the minimum value of an initial SRI of 82 or aged value of 64. For steep-sloped roofs, the minimum required values are an initial SRI of 39 or aged SRI of 32. These specific SRI values are indicative of a material that performs well in reducing heat absorption both when it is new and after it has aged.

Vegetated roof When incorporating a vegetated roof into the design, projects must prioritize the use of native or adapted plant species. These species are well-adapted to the local environment and typically require less maintenance and support local biodiversity. [78]

Nonroof and roof measures calculation Projects pursuing this option must confirm compliance with the combined roof and nonroof strategies by calculating the total area associated with each measure (e.g., nonroof, high reflectance roof, and vegetated roof areas) and dividing it by its weighted value. The total value of implemented strategies must meet or exceed the total site paving area plus the total roof area within the project’s boundary.

78 Why native plants matter, (n.d.), Audubon, audubon.org/content/why-native-plantsmatter#:~:text=Because%20native%20plants%20are%20adapted%20to%20local%20environmental,and%20perhaps%20the%20m ost%20valuable%20natural%20resource%2C%20water.

U.S. Green Building Council LEED v5 Reference Guide for Building Design and Construction, April 2025 Launch Edition 146