Rating System

LEED BD+C: New Construction, LEED O+M: Existing Buildings, LEED BD+C: Core and Shell, LEED BD+C: Schools

Rating System Version

v3 - LEED 2009, v3 - LEED 2008, v2 - Schools 2007, v2 - LEED 2.2, v2 - LEED 2.1, v2 - LEED 2.0

Inquiry

Our project contains low slope roof, steep slope roof, and vegetative roof conditions. All specified roof products meet requirement for EMITTANCE of .90 or greater based on ASTM E408-71. Project will need to perform a "Weighted Average" to attain required SOLAR REFLECTANCE. Due to steep slope roofs, low slope roofs, and vegetative roofs having different requirements for reflectance I am assuming when considering the weighted average base on "CIR SS7.1 12/5/2001" these three are to be considered separately. We have specified adhered membrane roof (energy smart light grey) (solar reflectance = .49) in both steep slope and low slope conditions, vegetative roof area (low slope), and recycled synthetic shake shingle (steep slope) (solar reflectance = .18). Low Slope Roof Required (6%): (75% x .65) = .4875 Actual Low Slope (adhered membrane) (100%): .49 Steep Slope Roof Required (59%):(75% x .25) = .1875 Actual Steep Slope (Recycled Shake Shingle 75%): .18 Actual Steep Slope (adhered membrane 25%): .49 Actual Average: .75(.18) + .25(.49) = .25 Vegetative Roof (35%) We also need clarification of interpretation of Solar Reflectance Value determined for the specified Recycled Shingle. Specified product is designed to lighten up and grey as part of its natural weathering process. Product pulled off of production line does not meet required values for reflectance. However, ASTM E903 tests performed after just 6 months of weathering indicated an average tested solar reflectance of .18. This value falls with-in the allowed weighted average to attain the point. This product also tested at .15 after three years which also passes Energy Star guidelines with out considering weighted average. We feel that using the 6 month weathered values for solar reflectance should be considered in this case due to the fact that our specified product attains required value after only 1% of its warrentied life (considering it has a 50 year unconditional transferable warranty and a 100 year life expectancy). Please comment as to whether the above assumptions are consistent with your intent for credit SS7.2 Reduce Heat Island (Roof) and will or will not attain credit. Thank you.