As more millennials graduate into better paying jobs, marriage and parenthood, real estate developers are doing all they can to entice this renter-nation generation in home ownership.

That means making urban homes more affordable, which means making them smaller. The tiny house movement may still be something of a novelty on home-remodeling TV shows, but in downtown Washington, D.C., as in other major cities, the tiny condo movement is moving quickly into the mainstream.