Raft foundation is a type of shallow foundation used to support structures, it is also known as mat foundation. Unlike any other foundation, this type of foundation are often used when;

1. When the soil has a low bearing capacity and cannot support the load of the structure.
2. Raft foundation is also used in areas where there's high water table.
3. It's also suitable for heavy loads such as high raising buildings.
4. It is used to ensure an even settlement of structure.

So, How Does Raft Foundation Looks Like?

You can see the reinforcement steel bar used to form the structural walls of the foundation, this is to create a large continuous slab that covers the dimension of the structure. It helps to reduce the pressure of the structure on the soil by spreading the load over a wide area of the soil. This also controls differential settlement of structure.

The formwork was done by an experienced carpenter, very neatly with adequate bracing to avoid pulling out during vibrating of the concrete.

You can see the spacing inside, this allows easy passage of the coarse aggregates to avoid blocking the passage of concrete

A waterproofing was done before carrying out the casting so as to protect the structure from moisture damaging

A blinding layer was provided before placement of the reinforcement bar to separate it from the soil and ensured adequate coating.

Thanks for reading and feel free to use the pictures for educational/project reference purposes.