Schatten may not be so far off (and may have made the sizes of the small houses too generous) 10m square is 3.1m on each side....I'm about to post this paper I found on slums in Bangladesh (present day - worth reading if you want to know how a large proportion of the world around us live), but bearing in mind they have no modern amenities, it's possible within the extents of fantasy to think that the house sizes would not have changed too much over the ages:
Slum dwellers lived in very small, mostly single room homes (Table 3.16). The mean size of a house/room in the six cities was 102.8 sq. ft., the median being 100 sq. ft. (9.55 m2 and 9.29 m2 respectively). In many of slums (46%), the average room size varied between 76 and 100 sq. ft. Slum dwellers in Dhaka usually lived in smaller homes/rooms compared with other cities. In one fifth of Dhaka's slums (20%), room size was below 76 sq. ft. (7.06m2), while in three-fifths of clusters (61%) size varied between 76 and 100 sq. ft. Only 2.2% of slums in Dhaka had an average room size above 125 sq. ft., compared with 34 percent in Chittagong, 25.6 percent in Khulna, 33 percent in Rajshahi, 15 percent in Sylhet and 43.9 percent in Barisal.