Vegetated fins sound nice and made plenty of waves when the General Services Administration announced the idea for a refurbish of a Portland, Ore., building, but now the GSA isn't so sure about the idea.

Originally, plans called for the green wall to climb 200 feet on the Edith Green-Wendell Wyatt Federal Building in downtown Portland. Now? Nobody knows for sure. The largely non-descript downtown concrete structure built in 1975 is getting a complete $133 to $135 million overhaul starting this fall.

The building received plenty of press after the renderings of the green wall were released, but when ENR tried to pin down the GSA on how it was going to happen they weren't too eager to say.

blog post photo
Rendering by Scott Baumberger, Baumberger Studio

Kevin Kampschroer, director of the federal office of high-performance green buildings, knows the vegetation is capturing the attention of the public, but without final cost estimates, the GSA doesn't want to commit to its plan. "What we don't want to end up with is in 30 years having to do this all over again," he says.

SERA Architects of Portland and Seattle-based Howard S Wright Constructors are working to determine the feasibility of the entire refurbish of the 18-story structure. One thing is known: there will be new energy-saving facades. But now that architects and contractors are looking closer at the green wall idea, there are question marks coming up on installation costs, possible performance issues on a wall that isn't shielded from the sun by any neighboring buildings and potential long-term maintenance concerns.

"Is it going to be the final solution? We don't know," Kampschroer says. "But we will have some form of shading."

Don Eggleston, president of SERA, says that 50 percent shade coverage is needed on the west wall—that is the wall in question—to mesh with the interior radiant cooling system. Potential failure of vegetation to substantially cool would throw off the entire structure's plan.

We do know that the northern façade will draw as much light into the center of the building, which is expected to be 90 percent daylit. The east and south sides will feature different versions of a double-wall system with two parallel facades that allows ventilation to have the stack effect of a chimney.

The interior will be renovated with a new mechanical system, energy-efficient lighting that halves lighting needs and a radiant heating and cooling system. "This is a very balanced approach," Eggleston says. "There are a lot of metrics on how the building needs to perform." 

With the expectation that the GSA will save $280,000 per year on utility costs, the overall efficiency of the building will increase 30 percent. By capturing rainwater and reusing it, there will be a 68 percent reduction in potable water use.

But all of those facts and figures aren't quite as fun as a massive green wall with fins. So, now it is a wait and see approach to find out the final decision and see just how green a federal building can actually be.