What is the functions of a foundation? What is the job of a foundation? • It carries the weight of the building • Transfers loads safely to the ground • It spreads the weight of the building • It provides a flat level surface in which to build on There are four different types of foundation: • Strip foundation • Trench fill foundation • Raft foundation • Pile foundation Choosing a foundation for a project depends upon a number of key factors: • The type of building structure • Soil conditions • Site constraints – e.g. the size and shape of the site layout In the construction of houses or house extensions, where the soil is good, a strip foundation is generally used. In the construction of large buildings that offer heavy loads a raft foundation is used. When soil is weak and poor quality, a pile foundation is used. Strip foundation Strip foundation Insulation Brickwork Block work Damp Proof Course Ground Level Trench blocks below ground Concrete foundation Damp Proof Course Insulation Trench fill foundation Trench fill foundations are a type of shallow foundation that avoids bricklaying below ground by instead almost completely filling the trench excavation with concrete. Typically, concrete is poured to within 150 mm of the surface ground level. This type of foundation minimises the excavation required, as bricklayers are not required to access the trench to lay bricks or blocks. It can also help to reduce the width of the foundation where below ground brickwork would require a wider footing. Trench fill foundation Insulation Brickwork Block work Damp Proof Course Ground Level Concrete foundation Strip foundation Trench fill foundation Raft foundation Raft foundation Raft foundation Raft foundation Insulation Block work Brickwork Damp Proof Course Floor Screed Insulation Damp Proof Membrane Ground Level Sand blinding Concrete foundation (deeper at the edges) Pile foundation Pile foundation Insulation Block work Brickwork Damp Proof Course Floor Screed Insulation Steel reinforced concrete pad Damp Proof Membrane Concrete Hardcore Pile (Bored and cast in situ)
