What does a mat or raft foundation primarily serve as?

A mat or raft foundation serves primarily as a single monolithic footing for supporting columns and walls of a structure. This type of foundation is designed to distribute the loads of the building over a large area, which is especially beneficial on weak or compressible soil conditions. By spreading the weight evenly, a mat foundation minimizes differential settlement and improves structural stability.

The construction of a mat foundation involves a single large slab that can cover an extensive area, providing a solid base for the entire building. This characteristic differentiates it from other types of foundations that might only support specific points of a structure. The effective load distribution and increased bearing capacity make mat foundations a preferred choice in certain environments, particularly where soil conditions may not be suitable for traditional footing methods.