Jettying

[5] A jetty is an upper floor that depends on a cantilever system in which a horizontal beam, the jetty bressummer, supports the wall above and projects forward beyond the floor below (a technique also called oversailing).

Jetty joists in their turn were slotted sideways into the diagonal dragon beams at angle of 45° by means of mortise and tenon joints.

The origins of jettying are unclear but some reasons put forward for their purpose are:[6] Jetties were popular in the 16th century but banned in Rouen in 1520 relating to air circulation and the plague, and London in 1667 relating to the great fire.

In the North African Maghreb, houses in medieval city kasbahs often featured jetties.

The House of Opus Craticum, built before AD 79 in Roman Herculaneum, has a supported cantilever.

A double jettied timber-framed building. The ends of the multiple cantilevered joists supporting the upper floors can easily be seen.
The under-side of jetties in Germany are sometimes decorated and called a windbrett (wind board). This is an example of a jetty supported on brackets.
Paul Revere House Boston, Massachusetts, US, built 1680. This is framed on a few cantilevered beams.
An example of a hewn jetty in Glattfelden, Switzerland
Jetties in French are called encorbellements and may be decoratively carved; Prieuré de Saint-Arnoult, France