Historic treasure gets 21st-century ecoroof

Rooftop plants help cut energy use, extend life of roof

By Jennifer Clampet

Pamplin Media Group, Jan 15, 2009, Updated Oct 30, 2009

JONATHAN HOUSE / PAMPLIN MEDIA GROUP

Mark Carpenter, center, Tualatin roofing contractor, talks about the benefits of an ecoroof with Alan Proffitt, Multnomah County Facilities Property Manager, on top of the main library branch.

When Multnomah County added soil and plants atop its historic downtown Central Library last year, it was a sure sign that the time in the sun for “ecoroofs” has arrived.

For years, roofing associations were so concerned about leaks they hesitated to endorse green roofs, which use vegetation to save energy, reduce stormwater runoff and improve air quality. But in July 2007, the National Roofing Contractors Association put out its first Green Roof Systems Manual.

Multnomah County’s Central Library, 801 S.W. 10th Ave., is one of Portland’s prized architectural treasures. The 1913 structure designed by A.E. Doyle is listed on the National Register of Historic Places. Now it appears to be the first library in Oregon, and the first historic building in the state, to boast an ecoroof, says Alan Proffitt, county facilities property manager.

The roof is expected to reduce library energy costs in the summer, and double or triple the life of the roof by protecting its structural elements from temperature extremes. The rooftop vegetation also will reduce the volume of runoff from the building.

The ecoroof employs a new patented technology from a Tualatin company that aims to make roof maintenance easier – and eliminate some of landlords’ concerns about installing ecoroofs.

Standing on the roof of the library one cloudy day in November, Mark Carpenter digs his finger into a tray filled mostly with plants in the “sedum” family – often traditional garden plants – with some splashes of color from lavender and grasses.

Carpenter is the president of Columbia Roofing and Sheet Metal of Tualatin, and its sister company, Columbia Green Technologies. He’s been in the ecoroof business for the last three years, since patenting the Advanced Vegetative Roof Systems. His system uses interlocking trays that can protect the roof from winds, while enabling easier access for roof maintenance.

“With an old ecoroof system, you have to dig up 8 inches to 10 inches of growing medium, cut the mat to get to the potential leak,” Carpenter says. “Then when you’re done, you have to cover with more mat, and it must be sealed to the old mat to keep that barrier.”

Columbia Green’s trays update the ecoroof idea, Carpenter says. Trays can be simply removed to get to problem areas instead of cutting and replacing mat. Other companies offer similar modular or tray systems, but Carpenter says his company’s technology is set apart, because the trays are connected by pins that enable the system to withstand wind uplifts.

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