Regulating Soil Moisture

The effect of Houston’s weather on your foundation

Virtually every summer in Houston we experience a minor drought. Even if the Houston Area as a whole receives a normal amount of rainfall, some neighborhoods may not. Watering your foundation will mitigate the effect of dry weather, but there is only so much it can do.

Once the subsurface soil drys out, it is very difficult to replenish the missing moisture without a period or prolonged rain.

The reality is that watering your foundation will not uniformly irrigate the soil at a depth to be as effective as you would like once the soil has dried out.

Trees and other large vegetation

You can control what you plant and where you plant trees and shrubs, but you have little control over how they grow and how they interact with the soil.

Shrubs that get very large and grow adjacent to the foundation should be removed. (In my experience, shallow-rooted shrubs like azaleas are rarely if ever an issue.) The effect of trees on your foundation can usually be effectively mitigated with root barriers.

Moisture migration in the soil

Believe it or not, but the movement of moisture and water through soil is a much studied topic in engineering. It is a active research area. There is much we do not know or understand. What we know for sure is that:

  • water and moisture does migrate through the soil in ways that are not always easy to predict
  • moisture and water moving through the soil can have severely destructive effects on building foundations

In the Houston area, water and moisture moving through the soil create drainage issues and perched water tables. Unfortunately, these issues can be difficult to diagnose or to cure.

What is reasonable to expect?

Clearly, there are limitations on what can be done to mitigate moisture changes in the soil supporting your foundation. But that does not mean you should not do those things that you can do.

Use root barriers where appropriate, make sure the drainage adjacent to the foundation is adequate, remove large shrubs adjacent to the house unless they are shallow rooted like azaleas, water your foundation using an automatic watering system and pay attention to the rainfall your neighborhood and house are receiving.

What is the potential payoff? From my experience, the measures discussed above can potentially reduce foundation movement by 50%. It may take 6-months to 3-years to see the actual result for your home. Every house will see a different result, but there is very little risk in doing what you can do.

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