What is unsuitable ground for house foundations?

Unsuitable ground for house foundations includes areas with loose or unstable soil, such as fill dirt or poorly compacted materials, which can lead to settling and structural issues. Similarly, expansive clay soils that swell and shrink with moisture changes can exert pressure on foundations, causing cracking. Additionally, ground prone to flooding or near water bodies can compromise stability and lead to moisture-related problems. Lastly, areas with high seismic activity may require special foundation designs to mitigate earthquake risks.