Soil instead of shingles

A building at Peterson Air Force Base will be in full bloom next spring after construction workers finish installing its flowering roof next month.

The project is a first in the region and is being closely watched by Pentagon planners weighing the virtues of “green roofs” that use soil and plants instead of shingles.

The roof is supposed to help reduce energy costs in the 21st Space Wing’s headquarters building, which is having its 19,000-square-foot roof covered with several inches of soil and planted with sedum, which is often used in rock gardens.

The soil is expected to improve the building’s insulation from low winter temperatures and the heat of summer, and the designers say the thirsty sedum, which stores water in its leaves, will eliminate 90 percent of the building’s stormwater runoff.

“There has been a lot of talk at the Air Force level about whether we can make this work,” said Randy Hawke, an architect at Peterson.

If the concept pays off, it could see wider use at bases around Colorado Springs and elsewhere.

Heidi Brothers, a project manager for roof contractor Weston Solutions, said natural vegetation roofs have been used in Germany since World War I, when they were introduced as camouflage.

In modern times, though, it’s been found that the roof concept can carve utility bills while virtually eliminating stormwater runoff. The plants on the roof also help the environment by breaking down greenhouse gases, Brothers said.

The Air Force in recent years has looked at a variety of options to shave its energy use, including initiatives to burn biodiesel in some of its planes.

The green-roof concept, Hawke said, expands those efforts.

“We want to show we’re environmentally friendly and be good stewards for the community,” he said.

Building a roof that’s designed to hold water is still a scary prospect for planners, Hawke said. Especially when that roof sits atop a building that contains millions of dollars in computer equipment.

“It was a hard sell,” he said.

But the plants, Brothers said, actually protect the underlying roof and increase its life expectancy while decreasing the possibility of leaks.

Installing the roof will run $17 per square foot, or more than $320,000 for the building.

It will be studied by Air Force leaders, who will watch utility bills while gauging the roof’s ability to keep out water.

Hawke said the studies will last a year.

The roof is unlikely to be noticed by people who work in the building. Because there’s a 4-foot-tall ledge surrounding the roof, the plants won’t be seen from the ground.

“It’s not for decoration,” Hawke said.

CONTACT THE WRITER: 636-0240 or tom.roeder@gazette.com