What do we call medieval houses built partly over the street in towns?

The story behind the answer

A jetty is the projection of an upper story beyond the one below, common in medieval timber-framed towns. Builders extended floor joists past the wall plate to create extra room above narrow plots, while keeping the ground level open for streets and shopfronts. Corner projections were supported by diagonal “dragon beams.” The overhang also helped shed rain and offered some shelter to pedestrians and market stalls.

These structures became iconic in late medieval and Tudor streetscapes across England, France, and Germany. Urban fire risk and street-narrowing eventually led to regulations curbing them—famously after the Great Fire of London in 1666. “Corbelling” refers more to stepped masonry, and “cantilevered” is a general engineering term; the historical technique and term here is jettying.