GBCI defines a minimum floor area requirement to earn MRc9

There's been a lot of discussion and questions in the past regarding whether there is some minimum amount of work required to earn this credit and MRc3. USGBC used the word "substantial" in the credit requirement and went on to say "at least 2 trades" and "one entire room" in the Reference Guide. In response to a credit appeal, GBCI issued the following statement to me, "Substantial alterations typically involve the relocation of walls or affect greater than 5% of the gross floor area." So despite this not being the official policy of USGBC, the caretaker and developer of the rating system and its requirements, it looks like GBCI has established this rule for 5% of the gross floor area. I hope this helps future project teams in their pursuit of MRc9 and MRc3.