Post in ground construction, also called earthfast or hole-set posts, is a type of construction in which vertical, roof-bearing timbers, called posts, are in direct contact with the ground. They may be placed into excavated post holes, driven into the ground, or on sills which are set on the ground without a foundation. Earthfast construction is common from the Neolithic period to the present and is used world-wide. Post-in-the-ground construction is sometimes called an "impermanent" form such as for houses which are expected to last a decade or two before a better quality structure can be built.
Post in ground construction can also include sill on grade, wood-lined cellars, and pit houses. Most pre-historic and medieval wooden dwellings were built post in ground worldwide.
This type of construction is often believed to be an intermediate form between a palisade construction and a stave construction. Because the postholes are easily detected in archaeological surveys, they can be differentiated from the other two.
Post-in-ground was one of the timber construction methods used for French colonial structures in New France specifically called poteaux-en-terre.
The Japanese also used earthfast construction they call Hottate-bashira (literally "embedded pillars") until the eighteenth century.
Some places the people still use post in ground construction such as the Toguna shelter of the Dogon people in Africa.
In the historical region of New France poteaux-en-terre was a historic style of earthfast timber framing. This method is very similar to poteaux-sur-sol but for the boulin (hewn posts) planted in the ground rather than landing on a sill plate. The spaces between the boulin were filled with bousillage (reinforced mud) or pierrotage (stones and mud).
Drawing of poteaux-en-terre in the Beauvais House in Ste Genevieve MO
A cross section of a poteaux-en-terre house.
A model of the Beauvais-Amoureux House, showing poteaux-en-terre construction.