When you can and when you cannot count one material as contributing to more than one credit in the Materials and Resources category of LEED has confused me for years. Even the LEED Reference Guide doesn't lay it out clearly. So, after sorting it out for LEEDuser, I thought laying it out in a table might help.

Here's an example. Cotton insulation is typically post-industrial recycled material AND it's a rapidly renewable plant material. So LEED allows you to count the cost of that material towards both MRc4 (Recycled Content) and MRc6 (Rapidly Renewable). If it also happens to be manufactured locally, in LEED-CI you could claim it towards MRc5 (Regional Materials) as well. Three-for-one! But if you're using salvaged timbers to earn MRc3 (Resource Reuse), you cannot also claim them as recycled materials for MRc4. Sometimes a material can count towards one credit or another — you can choose which, but you can't claim it for both. Of course, the fact that you're allowed to count one material towards more than one credit only applies if the material actually has the characteristics that both credits require. FSC-certified wood counts for MRc7 and MRc5, but it only gets the latter point if it actually was harvested and manufactured (or, for LEED-CI, just manufactured) within a 500-mile radius of the project. Anyone have further examples or experiences that might help clarify this situation?