If you watch, read, or listen to the news at all, you’ve heard about the hot weather and drought that the people in Texas have been enduring for the past month. In parts of the state, temperatures have exceeded 100° Fahrenheit (37.8° Celsius) for over a month. While it did dip below these record setting temps this past week, all indications point to continued above average temperatures for as much as three more months!
Along with being extremely uncomfortable outdoors (not to mention risking heat stroke), many residents are enduring city-side water restrictions brought on by water main bursts. In Houston, an astonishing 700 water main breaks a day have been reported. These high temperatures and dryness are also causing building damage in many homes. Sound strange? It’s not…and should have even been expected.
Everything’s bigger in Texas, and their expansive clay soils are no exception: free swell in the common clay soil montmorillonite can be as much as 1200%! The reverse is also true. If the “expansive” soil contains a certain amount of water naturally, and then is dried out – losing that water – it will shrink. The shrinking and swelling of expansive soils causes billions of dollars worth of economic loss in North America every year…more than floods, hurricanes, tornadoes, and earthquakes combined.
The current temperatures in Texas are drying out the clay soil, causing it to shrink and resulting in damage to buildings, roads, and all those water main breaks. In the case of buildings and roadways, this action causes differential settlement (some areas of soil will shrink faster than others). In many cases, the resulting damage won’t be too excessive, but have led to garage doors becoming misaligned and jamming, foundations cracking, rigid utility lines breaking where they enter the home, and so on. Void spaces can also develop and, when under roadways, may result in collapses (hopefully without causing an accident).
The 700+ water main breaks per day are also a result of shrinking soils. In this case, the high-pressure water mains are losing lateral support of adjacent soils when the soil dries, shrinks, and pulls away from the lines, leaving void space around the pipes. Combine that with the old, weakening metal pipes that are buried all over major cities like Houston, and you’re bound to have bursting pipes.
One thing to note is that the soil is now dry (or very nearly dry), and as moisture content begins returning to normal in the coming months, these same soils will begin expanding again. Why is this important? If damaged properties are fixed now, without taking this fact into consideration, they will now be risking damage due to swelling! It should be obvious at this point to understand what you are dealing with and how these soils will react to changes in the environment. Even the average homeowner should know what type of soil is on their property and the inherent risks involved (and what they can do to minimize those risks).