Discovery.com has the archaeological news of a house from Nazareth from the era when Jesus was born.
The dwelling and older discoveries of nearby tombs in burial caves suggest that Nazareth was an out-of-the-way hamlet of around 50 houses on a patch of about four acres (1.6 hectares). It was evidently populated by Jews of modest means who kept camouflaged grottos to hide from Roman invaders, said archaeologist Yardena Alexandre, excavations director at the Israel Antiquities Authority
The house, to date, is 900 sq ft, a pretty small home by American standards, even for a small family of four.
“According to the National Association of Home Builders, the average home size in the United States was 2,330 square feet in 2004, up from 1,400 square feet in 1970.” from Info Please.
My friends in Austin have a home from the 50s and theirs is typical for that era and area and is about 1200 sq ft. Another set of friends have a home there from the 40s and theirs was about 1400 sq ft. Our home in Abilene from the 40s was also about 1400 sq ft.
According to these sites the average was about 1100 to 1200 square feet in the 1950’s.
I know the three houses my family lived in the the 1950’s ranged from about 900 square feet to about 1400 square feet.
Outside the Beltway
from Yahoo! Answers