As of update 0.06 this feature was removed
A support was a buildable structure in Stranded Deep. A support, as the name suggests, helps to support the structural frame of one's shelter. Building a support needed the use of a single Wood Stick placed next to an existing foundation, as well as any type of Hammer to build and place it.
Once crafted, a support would be placed on any of the four corners of a foundation. At least two supports was needed to be placed adjacent to each other being able to place either a Door or a wall in between them; four (one in each corner) are required to be able to place a roof on top of them.It was removed from the game long ago.The info here is kept for historical info.