Housing is a serious problem in the SRV, particularly in urban areas of the north where war damage has caused overcrowding and lack of resources has hampered efforts to resolve the problem. By 1986, housing had become a critical problem in Hanoi, particularly in the central sections of the city, where per capita living space was reduced to four sq m. Large flats are gradually being erected in the suburbs to ease the problem. In the meantime, many families live in temporary quarters built directly on the sidewalk or attached to other buildings. Housing is less a problem in the countryside, where many farm families have begun to take advantage of a rising standard of living to build new houses of brick and stone. Similarly, in the south, housing is available to meet the requirements of the population because building construction had continued at a relatively high level during the war years. In 1989, the majority of housing units were semi-permanent (structures with brick walls and tile roofs lasting about 20 years).