by Thomas M. Simmons

In order to gain the LEED credits required for LEED certification of a building project, calculations must be utilized to determine whether the project meets a credit threshold. These calculations will also need to be recalculated during the design of a project to accommodate modifications and revisions to the design.

BIM software can help with this process, and ArchiCAD provides a good example. ArchiCAD cannot automatically validate your LEED certification; however, ArchiCAD's BIM database is an excellent system for the calculation of requirements for LEED credits that is typical during the life of a project. In addition, ArchiCAD's BIM engine can be used to verify project data and provide calculations for the certification process.

We will review how to create a "Sustainable Site" calculation for the LEED category, "SS Credit 7.2 - Landscape & Exterior Design to Reduce Heat Islands, Roof Surfaces." To qualify for this credit, a project must provide area calculations demonstrating that the green roof system covers at least 50 percent of the total roof area. In this example, we will set up an Interactive Schedule displaying the required data to produce a Roof Surface Calculation that can be used to meet the calculation requirements.

Step 1: Add Green Roof Materials to the Material Settings

In order to assign a green roof material to the roof, we must first add a green roof material to the Material Settings so that we can select this material in the Roof Tool. To begin this step, open the Material Settings from the menu Options > Element Attributes > Materials.

Within the Materials Settings dialog, select the "07 | Asphalt Shingle" material within the default settings, and click the Duplicate button. To create the new material, enter the new name for the material as "SS | GreenGrid Vegetated Roof."   >>>

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SUBSCRIPTION SAMPLE Step 1: Begin creating the Green Roof material in ArchiCAD by selecting the Material Settings dialog box, and duplicating the existing material definition for "07 | Asphalt Shingle." Image: ArchitectureWeek Extra Large Image SUBSCRIPTION SAMPLE Rename the duplicate definition "SS | GreenGrid Vegetated Roof." Image: ArchitectureWeek Extra Large Image   Click on thumbnail images to view full-size pictures.