The foundation is the structure which supports the rest of the building. In home construction it is the portion, usually under gound, that sits on top of the footing and can be made of either pressure treated lumber, concrete blocks or concrete poured in place.
Every foundation works to transfer the weight load of a structure to the soil beneath.
Types of foundation
• Shallow foundations
• Deep foundations
Most small and medium homes are built upon a shallow foundation. Larger buildings use a deep foundation rather than a shallow foundation.
A shallow foundation is a type of foundation which transfers building loads to the earth very near the surface, rather than to a subsurface layer or a range of depths
Shallow foundations (sometimes called 'spread footings') include pads ('isolated footings'), strip footings and rafts.
Shallows foundations are used when surface soils are sufficiently strong and stiff to support the imposed loads; they are generally unsuitable in weak or highly compressible soils, such as poorly-compacted fill, peat, recent lacustrine and alluvial deposits, etc.
• Pad foundations
• Strip foundations
• Raft foundations
Pad foundations are used to support an individual point load such as that due to a structural column. They may be circular, square or reactangular. They usually consist of a block or slab of uniform thickness, but they may be stepped or haunched if they are required to spread the load from a heavy column. Pad foundations are usually shallow, but deep pad foundations can also be used.
Strip foundations are used to support a line of loads, either due to a load-bearing wall, or if a line of columns need supporting where column positions are so close that individual pad foundations would be inappropriate.
Raft foundations are used to spread the load from a structure over a large area, normally the entire area of the structure....