Apartment vacancies rise on crowded Capitol Hill. (Residential Real Estate).

Since last year, the apartment vacancy rate in Seattle's Capitol Hill neighborhood has nearly doubled to 2.9 percent.

Vacancies are even higher in the more expensive buildings, those where a one-bedroom apartment rents for $900 or more a month, said Dan Swanson, a broker at Bellevue-based Marcus & Millichap who. focuses on the Capitol Hill market.

"The higher the rents are right now, the higher the vacancy rate," said Mike Scott, a partner at Seattle-based Dupre + Scott Apartment Advisors Inc.

But despite higher vacancies, builders are moving, ahead with new apartment construction, encouraged by the rising rents over the last five years. And investors continue to buy whatever apartment buildings become available in the neighborhood.

In general, Capitol Hill rents tend to be higher and vacancy rates tend to be lower than much of King County. But the wide range of apartments …