What type of soil is generally not recommended for setting building foundations?

Loam and peat soils are generally not recommended for setting building foundations primarily due to their organic composition and high moisture retention characteristics. Loam, while often considered good for gardens due to its balanced texture and fertility, can sometimes become unstable when wet. Peat retains a significant amount of water and has a tendency to decompose over time, which can lead to settlement and instability under the weight of a building. This can cause uneven settling and potential structural issues as the foundation may shift with changes in the moisture content of the soil.

In contrast, clay, gravel, and sand all present different characteristics. Clay can be challenging due to its expansive nature—expanding when wet and shrinking when dry, but it's still used in some foundation settings with proper engineering. Gravel and sand are typically more suitable for building foundations because they provide good drainage and stability. Gravel provides excellent load-bearing properties and drainage, while sand allows for good compaction and drainage as well.

When considering foundation settings, understanding the characteristics of different types of soil is essential to prevent future structural issues and ensure longevity and safety in the building process.