Our LEED site contains multiple buildings for a nature center, which covers a large acreage of land. In order to provide access to outlying buildings, elevated boardwalks are planned to be constructed on helical piers in order to preserve and protect the delicate ecosystems that are part of the site. These boardwalks will be built of composite lumber with gaps between the boards for water to run through. Since the boardwalks are not "impervious" to water, we are assuming that they will be considered pervious and therefore not meet the definition as one of the site\'s "non-roof impervious surfaces" for this credit. Before we proceeded under this assumption, we wanted to receive feedback on the likely outcome of this strategy. FYI: The supplier of the composite wood decking has not completed any ASTM E903 testing on its product to determine its reflectivity.
The boardwalk area must be included as non-roof impervious surface for purposes of the credit calculations. The intent of SSc7.1 is to reduce heat islands to minimize impact on microclimate and human and wildlife habitat. If the composite wood decking has a low reflectivity, it would contribute toward a heat island effect.Update April 15, 2011: Please note that all 2009 projects in multiple building situations must follow the 2010 Application Guide for Multiple Buildings and On-Campus Building Projects, located here: https://www.usgbc.org/ShowFile.aspx?DocumentID=7987. 2009 project teams should check this document for up to date guidance on all multiple building issues.