Residential GreenroofingGreg Haines, Project Manager

Turning Grey to Green,One Roof at a Time!

The concept of greening a rooftop is

centuries old.Church in Vidimyri, Iceland,

1834

Houses in Iceland, circa 1800’s

Photo: Greenroofs.com

Photo: Greenroofs.com

Houses in Iceland, circa 1800’s

It was early recognized that green roofs could improve a building’sdurability,

regulation of temperature, and overall

aesthetic value.

Residential building in GermanyPhoto: Greenroofs.com

The use of green roofs has increased significantly throughout

Scandinavia.

Ford dealership in Sweden

Photo: Greenroofs.com

Major corporations are beginning to see the benefits

of green roof technology.

GAP Inc. Headquarters, San Bruno, CA

Photo: Greenroofs.com

Photo Courtesy Tom Liptan

In Portland, as in most areas, stormwater is now recognized as the number one cause of degraded urban stream health. This is an especially serious issue for our Rainy City because our waterways once supported wild populations of salmon.

II. Benefits

Stormwater Mitigation:

Degraded Runoff

• Plants absorb rainwater for photosynthetic processes

• Plants reintroduce water into the air through evapotranspiration

• The soil acts like a sponge, absorbing water, much of which is released to the air through evaporation.

• These processes remove 30% to 50% of rainwater that falls on ecoroofs in Portland

• The effect on the storm sewer systems is a lower peak and a flattened curve for stormwater flow

• This effects temperature, peak flow, and quality of the remaining runoff

• There is Five Times more residential rooftop than Commercial Rooftop area– and this provides a

great opportunity to reclaim our watersheds!

The Rainwater Sponge

A 1,500 sq. ft. roof will shed 34,000 gallons of rainwater a year.

Sound Reduction:

• Absorbs both ambient and penetrating sound waves

• Sound insulation improved by up to 8 dB• Reflected sound reduced by up to 3 dB• Vegetation absorbs high frequencies• Soil absorbs lower frequencies

Graphic Courtesy ZincoflorPhoto courtesy of American Hydrotech

Building in the flight path of an Airport

Thermal Behaviors:• Surface temp reduction of 14 – 22 deg.F ( 4” of

soil)• Significant wind chill reduction, reducing heat

demand by 5% to 25%• Greenroofs function as either an insulator or heat

sink, depending on moisture level. Either way, they help mitigate temperature extremes.

• HVAC air conditioning units on greenroofs take in cooled air instead of superheated air

• Urban Heat Island Effect Mitigation

Graphic courtesy of Zincoflor

Cold

HotPhoto Courtesy Tom

Liptan

Other Benefits:

•Air Quality –Absorbs CO2 and Some Pollutants. Traps Dust, Releases Oxygen•Energy Savings:Functions as Either Insulator or Heat Sink, depending on moisture level•Wildlife Habitat and Greenspace Created up to 100% of Building Footprint•Livability: Buffers Noise, Eliminates Glare, Aesthetic Value, Psychological Advantages•Protection of Roof Surface Results in 2 to 3 Times Longer Life of Membrane

Beekeeper’s Roof Provides Nectar for His Native Honeybees

Ecoroof Atop Local Food Coop Includes Edible Herbs

•We Share Our Knowledgebase of Lower-Cost, Locally-Available Materials and Designs•EE Project Managers Can Help with Procurement and Delivery of Materials

An Example of Low Cost Materials, Used in an Ecoroof Costing $7.00/ ft2. Shown Here is Pond Liner, Filter Fabric, and Common Corrugated Drain Pipe.

Graphic Courtesy of Steve Cowden, The Oregonian

Advancing the Industry by Reducing the Costs of Portland Area Ecoroofs:

Hawthorne Hostel EcoroofInstalled August 2002

Less Likely to Leak than Asphalt or Shingles, And Lasts 2-3 Times As Long!

PCC Rock Creek Straw Bale Ecoroof

Installation

Thermoplastic Polyolefin TPO

Protection Board Installed

Celotex Protection Board

Perimeter Strips Screwed In Place

• The Membrane will be Heat Welded to these, to hold it down

Roof Drain Holes Drilled• The Roof Drain is made of Heat

Weldable Membrane. A watertight connection is very important.

Roof Drain Hardware Being Installed from Underside of

Roof • Simple Low

Cost Parts• Easy to

Source at Most Hardware Stores

• Not Complicated

Closeup of Installed

Drain• This will be

waterproofed in the next steps

Membrane Being Placed On Roof

Roof Drain Welded to Membrane and “Dog Ear” being Formed for Corner Detail

Close up of “Dog Ear”

“Dog Ear” Being

Welded with Heat

Gun

Perimeter Strips Welded to Membrane to hold it

down

Close up of Drain, Showing “Sleeve”

60% Pumice20% Recycled Paper20% Composted ManurePro-Grow Rooftop Ag. 1-1(Tualatin Or.

Resources

www.greenroofs.comwww.ecoroofseverywhere.comwww.greenerbuildings.comwww.portlandonline.com/bes/index.cfm?c=34663

QUESTIONS & ANSWERSwww.buildinggreen.com/auth/article.cfm?

fileName=080509a.xml TPO

www.uoregon.edu/~akwok/VSCS/Ecotrust02/W02ecoroof/new/frameworks/THpages/THhyme.html