1.DHHa tall building with apartments in it that does not have an elevator 无电梯的公寓大楼
2.DHHan apartment, office etc in a building like this 无电梯大楼里的公寓房[办公室等]
Examples from the Corpus
walk-up• He lives on the fourth floor of a walk-up building.• In her walk-up, there would be a bed.• She lived in a red-brick tenement in Chelsea, an old walk-up building with gloomy stairwells and peeling paint on the walls.• The Kelly factor is big, and Rodman also had a big impact on our walk-up.