If a building is experiencing heaving, what is the likely cause?

Heaving in a building typically occurs when the soil beneath it expands, which is most often due to changes in moisture content. When soil, especially clay, absorbs water, it can swell significantly. This swelling forces the ground upward, causing the structures above to rise or become uneven. This phenomenon is contrary to settling, which involves soil compacting and sinking.

In this context, while ground settling, structural overload, and drainage issues could lead to other types of structural problems, they do not directly cause heaving. Ground settling refers to a decrease in land elevation usually associated with consolidation of soil or emptying out of voids. Structural overload can lead to failures or distortions but does not typically cause the ground to rise, while drainage issues primarily affect water management on and around the structure rather than causing direct heaving of the soil. Thus, soil expansion is the most accurate cause of heaving.