David L. Ryan/Globe Staff

Susan Mai viewed Boston from the roof at her small Beacon Hill apartment. Her devotion to city living is part of a trend.

David L. Ryan/Globe Staff

Almost everywhere you look, it seems, is a new building site in Boston. People are moving back into the city.

David L. Ryan/Globe Staff

More than 5,300 homes are under construction in Boston.

John Tlumacki/Globe Staff

The Factory 63, a newly renovated building in South Boston, includes apartments as small as 375 square feet.

David L. Ryan/Globe Staff

Housing is going up quickly to meet demand — in 2010 alone, Boston’s population grew by 7,500 people and is now above 625,000.

John Tlumacki/Globe Staff

The average rent in Boston is $1,700, but there are many at $4,000 or more.

David L. Ryan/Globe Staff

Crews worked on the upper floors of The Kensington, a new apartment tower going up along Washington Street.