Hanging rooftop pool will let you look 26 stories down

If you’re afraid of heights, you should stop reading.

An apartment tower planned in downtown Des Moines would include a swimming pool that hangs over the edge of the 26-story building — giving swimmers a view straight down, according to plans for the project released Friday.

In engineering terms, it’s called a cantilevered pool. Like a visor on a baseball cap, it would stick out about 11 feet from the top floor.

Developer of Des Moines skyscraper wants to break ground this fall

The sides of the pool would be made of glass and the bottom of the pool would include a glass panel for swimmers brave enough to look down.

Blackbird Investments, a Des Moines real estate development firm, is building the $85 million apartment tower at the corner of Seventh and Walnut streets.The pool will add roughly $250,000 to the project cost, said Justin Doyle, a partner in Blackbird Investments.

“It’s worth it for the interest” it will create, he said. “It will be an icon.”

The pool will stick out from the west side of the building, offering views of 801 Grand and the Pappajohn Sculpture Park.

Measuring 22-feet by 22-feet, the pool will hold nearly 11,000 gallons of water, which will weigh about 91,000 pounds. The structure is designed to hold twice as much weight, said Channing Swanson of Neumann Monson Architects, which designed the building and the pool.

The pool walls will be 6 inches thick, made of 10 layers of laminated glass. The layers allow the glass to retain its structure in the "improbable" case that one layer breaks, Swanson said.

“I’d feel better, honestly, driving my truck on that glass than most steel,” Doyle said.

Sadly, the pool will be open only to tenants.

Such cantilevered pools are not new. You can find them on cruise ships and in posh hotels and condo buildings in major cities and tourist destinations.

But for a small, Midwestern city, it's a novelty.

Blackbird Investments wants to break ground this fall and hopes to open the 276-unit apartment complex by mid-2018.