What is BOF ?
Definition of BOF in Construction Bottom of footing. This is an elevation designation that is commonly used on contract documents by engineers and architects. The BOF is important to establish the depth of the footings as well as the relationship with the surrounding grade elevations. Frost is a consideration in northern climates when engineers identify the BOF. The temperatures of the winter months will cause the ground to freeze. The BOF must be well below the depth that the ground freezes to eliminate the possibility of expansion and uplift as the ground freezes. Sitework contractors need to identify the BOF to determine the excavation depths for the footings. It is a very important elevation due to the fact that this elevation will establish the entire elevations of the structure. Failure to properly identify the BOF and design accordingly can result in devastating consequences. Professional surveyors are normally employed on major construction projects to properly and expertly establish the BOF for the project.