Vegetated Roof or Hardscape?

If the terrace is not within the building's enclosed Gross Floor Area, then you cannot count the vegetated areas in the terrace as a part of the "Area of Vegetated Roof" calculations. That being said, the terrace does have high-reflectance hardscape, so you can probably count that as a part of the "Area of Nonroof Measures."

The USGBC wording specifically states about Gross Floor Area, "Excludes non-enclosed (or non-enclosable) roofed-over areas, such as exterior covered walkways, porches, terraces or steps, roof overhangs, and similar features." (https://www.usgbc.org/help/what-gross-floor-area).

I would probably assume that if your terrace was a fixture of the roofed area, as in it does not leave the enclosed Gross Floor Area, it should be fine. If it is an actual terrace that is an extension of the roof, then you cannot.

I believe you can and should count the vegetated SF only as qualifying vegetated roof; the hardscape portions of the roof should be recorded in the "High Reflectance Roof" area in the form, with the vegetated SF in its own area.

Michael, the GFA does not play into the calculations for this credit. The heat island aspect is looking at site hardscape and roof area, neither of which are included in the project's GFA.

Tricia, is the terrace covered by anything, like a shade structure or other? If yes, that cover would be included in the calcs rather than the actual roof surface beneath. If it is not covered and is just an open area that happens to have some vegetated area combined with some walkable areas, seating, etc., then it can and should be included in the calcs. 

Hi, 

Would the area of the vegetation of the terrace still go into "Area of Vegetated Roof" in the above scenario? Would the terrace be considered a roof because it is accessible by or connected to the roof? Wouldn't the entireity of the terrace, both its high-reflective hardscape and vegetation, go into "Area of Nonroof Measures" for the calculation? If the terrace was not accessible by rooftop, would the scenario change?

I am not trying to argue. Just wondering and trying to learn.

RIght, this is good dialogue. I have found that people/projects define terraces differently, and that does seem to matter to the reviewers. Tricia's description sounds to me like it's a portion of the roof, itself, that is specifically designed for access, including some vegetated areas. Perhaps that's just my interpretation of the statement. Some projects have on-roof terraces, like a slightly raised decking area on the roof, itself, for example. That definitely would be calc'd with the roofing materials. We learned in a previous post that a feature that is more like a balcany extended away from the building and not covering any enclosed space below would probably not be roof, and would, indeed, be in the non-roof calcs. I think your last statement was the right/same conclusion, just not quite the right way to define it. I can see the logic better now of what you were explaining.

That previous post is here: https://leeduser.buildinggreen.com/forum/how-calculate-multi-level-decks...

If for some reason that link doesn't work (pasting links just doesn't always work from my computer for some reason), it's a thread under this credit titled "How to calculate multi-level Decks / Patios". You should be able to use the word search feature in this credit's discussion page to find it that way. 
Even with an answer from LEED Coach, it seems there may still be cases where it could go either way.

Awesome, thanks!