The two main types of foundation are :

- Shallow foundation (spread foundation)
- Isolated footing
- Combined footing

- Deep foundation
- Pile foundation
- Pier foundation

#### Shallow foundation

Depth of foundation is less than or equal to its width.

#### Isolated footing

- In framed structures where several columns are to be constructed, isolated footings can be adopted.
- The columns involved can be provided with masonry or concrete footing.
- If masonry footing is provided, steps are given and the foundation area is thus increased so that the stresses developed at the base is within the limit.
- In case of masonry footing, the projection of each step must be Â½ brick thick and each step is made of 1 or 2 bricks put together.

#### Combined footing:

- This type of footing is adopted when the space between two columns is so small that the foundation for individual columns will overlap.
- Combined footings are proportioned in such a way that the center of gravity of the loads coincides with the center of gravity of the foundation. Hence these footings have either a trapezoidal or a rectangular shape.

**Pile foundation**

- A slender, structural member consisting steel or concrete or timber.
- It is installed in the ground to transfer the structural loads to soils at some significant depth below the base of the structure.
- Pile is an element of construction used as foundation. It may be driven in the ground vertically or with some inclination to transfer the load safely.