A doorframe functions as a wall, providing structure to a building and enclosing an area, but with the addition of hole to allow entrance and exit.
An Adobe Doorframe can be placed on any Foundation, Fence Foundation, Ceiling (with the exception of the Thatch Roof), or another wall.
A Door can be placed in the hole and locked to provide a way to restrict access to the structure while still allowing you and your tribemates a way through.
A doorframe also provides support to allow a structure built on top of it to extend up to 2 ceilings in any direction on the x and y-axis, and up to 1 ceiling diagonally from a doorframe which is directly above a foundation.
The insulation provided by a house is not affected by doorframes, whether the door is open, closed, or missing.
If a doorframe is destroyed, any building pieces that rely on it for support will be destroyed as well. If it was destroyed via the demolish option, no resources will be refunded for these extra building pieces.