From 《
汉书·
司马相如传下》 (biography of Sima Xiangru):
故鄙谚曰:家累千金,坐不垂堂 - 'thus the proverb says: a household worth a thousand pieces of gold does not sit beneath the eaves.'
垂堂 refers to the dripline of a roof. Sitting there risked falling roof tiles, a real hazard in Han architecture.