Dear all,
We are working on a project looking to incorporate a green roof for 100% of the roof area, excluding areas covered by mechanical equipment. However, the green roof will be made of modular trays that cannot be walked on and, therefore, maintenance paths for access to the mechanical equipment need to be provided. The project wants to earn the exemplary performance point for achieving 100% green roof. The question is whether the paths for maintenance can be excluded from the calculation in the same way the mechanical equipment is, mainly because access cannot be granted through the vegetated roof surface because of its nature? Thanks in advance for any insight.
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Mara Baum
Partner, Architecture & SustainabilityDIALOG
674 thumbs up
January 16, 2014 - 11:59 am
Unfortunately you can't exclude the maintenance pads. (IMHO this is a problem with the credit and the EP threshold should be 95%, as with things like construction waste management, but it is what it is.)
Michael DeVuono
Regional Stormwater LeaderArcadis North America
LEEDuser Expert
187 thumbs up
January 16, 2014 - 1:11 pm
Has this been tested, Mara? No green roof is ever 100% green. I would submit this and make them tell you no.
Can you do some form of elevated walkway to get where you need to go?
Susan Walter
HDRLEEDuser Expert
1296 thumbs up
January 16, 2014 - 1:25 pm
If your maintenance pads are SRI compliant, I would submit it for EP also. Review your layout and minimize the paths. Do everything you can to minimize the paths. The only thing they can say is no and you may be able to get a better reading on the topic from a reviewer.
We did a project that used 14,000 s.f. of vegetated tray system. The rep at the time said that the trays could handle some traffic but to keep it to foot traffic for plant maintenance only. Mechanical equipment can require more than that and you would need pavers of some sort.
But Mara is often right about these things...
Mara Baum
Partner, Architecture & SustainabilityDIALOG
674 thumbs up
January 16, 2014 - 1:26 pm
There's certainly nothing wrong with trying - it would be a design phase ID credit, and you can always submit a new one in construction.
I previously have been required to include walking pads as part of the calculation - they not an exclusion such as an appurtenance - but that may have been a reviewer judgement call.
I totally agree that green roofs aren't 100% green, hence my comment about the innappropriate threshold. However, many green roof designs still allow for walkable surfaces within the same system, which this one does not.
Mara Baum
Partner, Architecture & SustainabilityDIALOG
674 thumbs up
January 16, 2014 - 1:27 pm
Susan and I posted simultaneously just now. I totally agree that if you try an EP, you definitely want SRI compliant pads. You should definitely give it a shot.
Also, if it's a very small green roof then the pads may be a high percentage, in which case it wouldn't look as good.
Michael DeVuono
Regional Stormwater LeaderArcadis North America
LEEDuser Expert
187 thumbs up
January 16, 2014 - 1:34 pm
Carlos, if you attempt this, be sure to check back, and let us know how it goes.