Foundation issues

[Art Tompkins]

I was told by a semi reliable source that because of the drought, dirt is pulling away from foundations causing the possibility for shifting. Can anybody verify this is a real issue to be addressed?

[Eric Barker]

This can occur. Soil is like a sponge - it dries out it shrinks. Where things get interesting is when the soil under the footings begin to shrink and the foundations begin to loose their support. But this can be the first part. As the soil regains its moisture it will swell and push back up in the footings / foundations.

[Scott Patterson]

I was told by a semi reliable source that because of the drought, dirt is pulling away from foundations causing the possibility for shifting. Can anybody verify this is a real issue to be addressed?

If you are in an area with expansive soil(clay), YES it can be a problem... Unless you are in an area that you know it is an issue I would not worry about it.

When I lived in Mississippi it was a major issue as we were lucky to have what is called Yazoo Clay. It is basically bentonite and it expands and contracts on the order of 10X its volume. We had more foundation problems than Nolan Ryan could ever think about in his lifetime!

[Art Tompkins]

So, under drought conditions with the water table dropping, the soil under the foundation can dry out and cause problems not present under normal conditions??

[Scott Patterson]

So, under drought conditions with the water table dropping, the soil under the foundation can dry out and cause problems not present under normal conditions??

Bingo!

[Mark Fisher]

The main thing to be concerned with is uneven wetting/drying that leads to differential expansion/contraction under the footing. For example, if everything is bone dry and has been for months, then one corner gets swamped by a disconnected downspout, you will have more potential for problems than if all areas are evenly brought back to normal moisture levels.

There is a huge range of potential expansion/contraction depending on the soil type. The 4 basic classifications are: clay and silt (considered 'fine'); sand and 'gravel' (considered 'granular'). Most soils are some combination of the four and by general principle the more 'granular' a soil is, the less 'expansive' it is.

So, while it is true that what your source told you is technically correct, how big a problem it is will vary greatly, and there is little way to know without knowing the characteristics of the soils typical to your area.

[Lou Wissner]

Being on the Texas Gulf coast, where our are extremely expansive, it is a real concern. Since we have been having a drought for the past several years, we are seeing more and more extensive foundation concerns. I have began recommending my clients to place a soaker hose on the perimeter of the structure to stabilize the soils. Now I am not suggesting to have a muddy mess, because that can create another problem, but keeping it moist will help with maintaining the foundation.
lou
allcaosthomeinspections.com

[Lon Henderson]

I am, originally, from West Texas. There, people watered against their foundations to keep the sandy loam soil damp.

But here, we have extensive bentonite in our soils. No one would ever recommend wetting the drainage apron around a house. We engineer our houses to stay in place on a dry footprint. Water can change all that..........and does constantly.

So, the point of this is, you have to know what the soil conditions and construction practices are for your area. It ain't the same everywhere.