Extreme weather events, natural disasters, long periods of drought, rain and cold have strong effect on the soil under the structures and on the foundation.
The summer of 2018 was extraordinarily warm, and the heat lasted for a long time. At the same time, January was one of the coldest in history. While some people were exhausted from record high temperatures, other regions suffered from flooding. Rainstorms and cyclones had a devastating effect on many buildings and population in general.
How weather phenomena affect soil
Soil types vary by properties and their response to weather conditions, and they may have serious impact on load-bearing structures of buildings. Houses built on loose soil, sand and reactive clays (rising soils) may suffer the most due to seasonal or extreme rainfall, floods and drought (or cold).
Reactive clay expands when exposed to moisture and shrinks when drying. This is accompanied by soil splitting during long periods of drought and expansion during humid periods. Clay loses its porous structure as a result of freezing and expansion in cold weather.
Sand and loamy soils tend to subside due to rainfall, because water flushes off small particles and larger particles sink.
Filling material used in construction often consists of soil, but also other materials, such as brick or concrete fragments, also crushed construction materials. When water finds its way through such material and flushes away minor particles, it may cause the soil to sink. The effect of the process can be visually depicted as recess in the ground, whereas it may further deepen due to poor soil compaction and general condition of surrounding soil. In case of changes in the condition of soil under a structure, it can no longer support the foundation and the structures gradually start to sink. Building sinks either partially or entirely, but in any case, unevenly. This is called soil subsidence.
