Charles Ellicott Commentary Deuteronomy 22:8

"When thou buildest a new house, then thou shalt make a battlement for thy roof, that thou bring not blood upon thy house, if any man fall from thence." — Deuteronomy 22:8 (ASV)

When thou buildest a new house. —Obviously the Law refers to houses with flat roofs, upon which it was customary to walk (1 Samuel 9:25–26; 2 Samuel 11:2).