city of san jose police southside substation green roof€¦ · city of san jose police southside...

City of San Jose Police Southside Substation

Green Roof

Mirabel Aguilar, Associate EngineerPublic Works Department

June 2, 2011

City of San Jose Police Southside Substation Project

The largest project funded by the Neighborhood Security Act Bond Measure passed in March 2002

The Police Southside Substation is located along Great Oaks Parkway at Perimeter Road north of Highway 85, southeast of Highway 101

Construction Started in February 2008

Construction Completed in October 2010 (Beneficial Use)

Construction Cost approximately $68M

Premium cost associated with the installation of a Green Roof – approximately $300K

The Green Roof was incorporated in the substation’s design and drainage plan as part of the stormwater management elements required to achieve LEED Certification

City of San Jose Police Southside Substation

City of San Jose Police Southside Substation Green Roof

City of San Jose Police Southside Substation Green Roof

Extensive Green Roof • Typically 15 – 50 pounds per square foot• Vegetated with hearty native ground cover that requires

little maintenance• Solely for environmental benefits (not an accessible roof

garden)

Green Roof / Living Roof Designer

Rana Creek Living ArchitectureMonterey, CA

City of San Jose Police Southside Substation Green Roof

Living Roof Plans requires extensive coordination between:• Architect• Living Roof / Green Roof Designer• Structural Engineer• Civil Engineer• Mechanical Engineer

Potential Credits for LEED Certification – Green Roofs• Sustainable Sites (Stormwater Management, Heat Island

Reduction) • Water Efficiency• Energy and Atmosphere• Innovation and Design Process

City of San Jose Police Southside Substation – Drainage Plan

City of San Jose Police Southside Substation Green Roof – Basin/Bioswale

City of San Jose Police Southside Substation Green Roof – Design Elements

Elements of Vegetated Areas• Waterproof membrane applied to roof area• Membrane Reinforcement (second coat)• Root Barrier/Protection Course • Drainage Mat (Geotextile fabric to convey subsurface water to drains)• Water Retention Fleece (retains added water that runs through soil medium, i.e. rainfall)• Green Roof Edge Restraints• Filter Fabric (wrapped around edge restraints)• Irrigation System• Engineered Roof Soil• Plant Material (BioTrays)

City of San Jose Police Southside Substation Green Roof – Design Elements

Elements of Vegetation Free Zones • Drainage Rock • Ornamental Rock Cover• 3-inch perforated pipe (to capture water along downslope edge and convey water to drain)

Irrigation System• Drip System• Sized to provide 50% evapotranspiration rate• System programmed to a reduced watering schedule after plant establishment period

City of San Jose Police Southside Substation Green Roof – Drainage Areas

City of San Jose Police Southside Substation Green Roof – Irrigation System

City of San Jose Police Southside Substation Green Roof - North

City of San Jose Police Southside Substation Green Roof - North

City of San Jose Police Southside Substation Green Roof – North and

South

City of San Jose Police Southside Substation Green Roof - South

City of San Jose Police Southside Substation Green Roof - South

City of San Jose Police Southside Substation Green Roof – Structural Plan

City of San Jose Police Southside Substation Green Roof – Structural

Loads

City of San Jose Police Southside Substation Green Roof – Plant List

City of San Jose Police Southside Substation Green Roof

City of San Jose Police Southside Substation Green Roof

City of San Jose Police Southside Substation Green Roof – Irrigation System

City of San Jose Police Southside Substation Green Roof – Vegetation

City of San Jose Police Southside Substation Green Roof - BioTrays

City of San Jose Police Southside Substation Green Roof

Challenges/Lessons• Designed with subsurface irrigation system so requires other

method of watering during establishment period (60-days)• Requires fall protection measures and properly trained

personnel (per Cal/OSHA requirements) to install and maintain the green roof

• Weed abatement program should be in place as soon as plant material is installed

• Include volunteer plant species list • Limited surface area to incorporate walkways and paths• Contractors should be properly trained to work in the vegetated

areas without destroying the vegetation• Proper installation of all elements of the green roof is essential

City of San Jose Police Southside Substation Green Roof

Time for a movie! ☺

Time lapse video of the green roof installation spans approximately 5 months

City of San Jose Police Southside Substation Green Roof

Questions?