Foundation
Foundation is an architectural object in The Sims 2, The Sims 3 and The Sims 4.
Foundations are used to raise the level of the main floor and can be used over uneven terrain[TS2][TS3]. In The Sims 2, unpatched versions of The Sims 3 base game, and The Sims 3 for console, foundations are required for the construction of basements.
The foundation tool is used by clicking and dragging an a square area on the terrain. There is also a diagonal foundation tool.
Players can choose either a decking foundation, an elevated foundation, or a brick foundation. With the Late night oatch of The Sims 3, a new platform tool is introduced. It allows a player to create a flat elevated by a half-inch floor surface for sims to step on. Unlike the foundation tool, it doesn't confine a space and define it as a room.