We have a question regarding how to count the area of a curtain wall that will be replaced in C+S renovation project. Should the entire surface area of the curtain wall be counted, considering it as the building's envelope, or should it not be counted, considering it as a window assembly?
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April Brown
Sustainable Building ConsultantGreen Bridge Consulting
LEEDuser Expert
41 thumbs up
June 17, 2014 - 2:12 pm
Hi Patrizia,
Wow - that's a tough one and there are no LEED Interpretations on this question, surprisingly. Given that the primary function of the curtain wall is as a structural wall, I would considered the area as structure and therefore documenting that it is not being reused (as opposed to being exempted as a window assembly). If, some how, you are maintaining the structural elements and replacing the facade, you could make a case for building reuse.
Charles Nepps
NH Green Consulting97 thumbs up
September 19, 2014 - 7:50 am
Patrizia, did you ever get an ruling from LEED on this topic? I currently find myself in the same situation. Although not a structural element, curtain walls are certainly an envelope element, but could also been seen as a window assembly. In our particular case we are only replacing the glass, the existing mullions remain...just to make it more interesting.
Charles Nepps
NH Green Consulting97 thumbs up
October 7, 2014 - 5:44 pm
UPDATE: I sent the question to GBCI and got this response:
"Thank you for contacting USGBC regarding MRc1.1, and how to address curtain existing wall systems in the calculations of this credit. Excellent question. Curtain wall panes along with any mullion, sill, and head elements of the curtain wall assembly, are considered "window assembly" elements for the purposes of this credit, and therefore should be excluded from the numerator and denominator of the calculation. I hope that helps, but feel free to contact us again if you have further questions."