Forum discussion
NC-2009 SSc7.2: Heat Island Effect—Roof
In calculating compliant roof area to total roof area, is the SF associated with parapets considered roof area? Or is it considered wall and thus not applicable, or an appertenance?
Either way, I shouldn't have a problem on my current project, but in the event of a project where it is tight in earning the required 75% threshold, does anyone know the answer? Thanks!
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Charles Nepps
NH Green Consulting97 thumbs up
June 8, 2016 - 10:55 am
Interesting question. I see a lot of non USGBC literature that states:"excluding parapets,sky lights, and equipment..." However the LEED Ref Guide uses the language "mechanical equipment, solar energy panels, and appurtenances..." I would assume "parapets" fall under the catchall category of "appurtenances", so the horizontal component should be deducted from the total roof area for purposes of the calculation. However since you'll essentially be increasing the total roof area by the square footage of the top of the parapet wall, then deducting it back out, seems like it would be a wash.
Renee Shirey
Stantec422 thumbs up
June 8, 2016 - 11:02 am
Thanks for the quick response. I was thinking similarly, and just wasn't going to include it (or highlight it on a plan) as part of the roof total, since in my opinion it shouldn't be counted towards/against the % of compliant roof. I just started to overthink it, plus as we go on with the process of LEED I have learned that an approach to a credit that worked in the past no longer works.
Charles Nepps
NH Green Consulting97 thumbs up
June 8, 2016 - 11:33 am
I completely understand; it's definitely a learning process, not just for us, but for the review teams as well. I agree you can't always be certain that past methods will be successful on current projects, but I have notice more consistency in the last 12 months or so; seems to be headed the right direction.
Summer Minchew
Managing PartnerEcoimpact Consulting
LEEDuser Expert
170 thumbs up
June 8, 2016 - 2:26 pm
Technically, yes, the parapet is part of the roof and should be included in the credit calculations. That said, the reality is that the parapet is typically such a small part of the overall roof that it doesn’t play a factor in credit compliance and most teams don’t include it in the calculations. You might reference LEED Interpretation 1441 which gives guidance on a unique parapet situation in case that is relevant to your project.