Determine the value of assemblies by separating each component by weight as a percentage of the total. For example, if a $100 piece of built-in casework contains 80% (by weight) salvaged wood and 20% (by weight) new marble, $80 worth (80%) of the casework would contribute to this credit, because that is the proportion that is reused. (See the Reuse Assembly Calculator in the Documentation Toolkit for help making these calculations.)