Dawson Foundation Repair
Dawson Foundation Repair
Dawson Foundation Repair

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Subsidence – Coming Soon!

Posted by on Aug 12, 2014 in Learn | 0 comments

Land Subsidence – a Gradual Enemy

The continuing drought in California has led to accelerated groundwater pumping from San Joaquin Valley aquifers. This is nothing new for this part of California, but the intensity of the pumping during the last few years is unique.

Pumping groundwater from the San Joaquin Valley began in 1926 and some areas have seen land subsidence in excess of 28 feet. Today the experts are sounding the alarm because subsidence is now one foot per year in many areas.  See a Photo from on U.S. Geological Survey site showing the extent of Land Subsidence

What is Subsidence?

Land subsidence (or subsidence) is the settlement (reduced elevation) of the ground’s surface. It is usually due to the movement or removal of soil, minerals, or water from under the surface. Most subsidence is “man-made,” however, some cases can occur naturally from sinkholes, thawing permafrost, or natural compaction.

How does Subsidence affect Texas?

The soil in the southeast portion of Texas is comprised of clay, sand, and water. When the water is removed the land sinks.  This is the nature of the geology of the area. When the land sinks, ground faults are created and/or expand.  Soil movement – sinking or settlement – damages foundations, buildings, water lines, and pipelines. 

Perhaps the most dramatic example of subsidence in Texas has occurred in the Brownwood subdivision of Baytown, Texas, twenty miles east of downtown Houston. It is a subdivision of 448 homes, most of which are sitting in 10 or 15 feet of seawater of Crystal Bay. It is the result of the aggressive groundwater extraction of the southeast Texas Evangeline and Chicot aquifers that began in 1943.

In a 1974 Texas Monthly article the author states that over 20,000 acres of land area around Galveston has or will soon sink into the Galveston Bay and it estuaries. He also pointed out that over $100 million in property has been lost and that in Texas City and Pasadena the storm sewers have water flowing in the wrong direction. 

This Texas Monthly article also states that more than 1000 miles of faults can be “activated” by the threat of subsidence – which in turn threatens residential, commercial, and industrial buildings. The Woodlands has recently seen problems with faults and some homes are being literally torn apart by fault lines that widen every year. We discussed these Texas faults in an earlier blog post.

Currently, the northwest corner of Houston is one of the areas experiencing the greatest subsidence. Home owners and home buyers should be aware of the long term risks associated with land subsidence.


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Are We There Yet? The Drought of 2014?

Posted by on May 28, 2014 in Learn | 0 comments

The Drought of 2014

The official beginning of summer has yet to arrive but more than 90% of Texas is officially classified as “Abnormally Dry” or worse. The summer droughts of 2011 and 2013 were brutal and caused extensive damage to homes and home foundations. What do the “dog days” of summer 2014 have planned for us?

Severe Droughts will cause significant foundation damage to homes in Texas

Texas Drought Map – May 20, 2014

As of May 20, 2014 the U.S. Drought Monitor has published the following statistics regarding Texas and its drought status.

90.18% of Texas is “Abnormally Dry” or worse
72.31% of Texas is “Moderate Drought” or worse
56.11% of Texas is “Severe Drought” or worse
40.35% of Texas is “Extreme Drought” or worse
25.05% of Texas is “Exceptional Drought”

In addition to the discouraging numbers above the drought in Texas is classified as both short-term and long-term. Short-term is considered six months or less and affects agricultural and grasslands most acutely. Long-term is considered six months or longer and affects hydrology and ecology most acutely.

For comparison purposes, the drought status for Texas on May 28 of 2013 is below.

96.51% of Texas was “Abnormally Dry” or worse
88.27% of Texas was “Moderate Drought” or worse
60.34% of Texas was “Severe Drought” or worse
32.45% of Texas was “Extreme Drought” or worse
16.02% of Texas was “Exceptional Drought”

To further compare, the drought status for Texas on May 24 of 2011, one of the worst droughts in history, is below.

97.70% of Texas was “Abnormally Dry” or worse
95.77% of Texas was “Moderate Drought” or worse
91.97% of Texas was “Severe Drought” or worse
78.45% of Texas was “Extreme Drought” or worse
43.97% of Texas was “Exceptional Drought”

What does this all mean? The predictions are for a dry, hot summer. If there is little or no rain then we can expect a drought as bad as 2013 and perhaps as bad as 2011. It all depends on the weather patterns and the amount of rain we have in the next three months.

The reason droughts affect concrete slab foundations so dramatically is because the clay soils in Texas will shrink in volume when they lose moisture. With plants and trees withdrawing moisture from the ground, and severe drought conditions present, the clay soils will shrink dramatically. When the clay soils shrink they “pull away” from the foundation perimeter and leave a gap between the soil and the bottom of the concrete foundation. When this gap becomes too large the weight of the home and foundation will crack the concrete slab and it will “fall down” until it reaches something to support it, which is the shrunken soil. The term used to describe this process is settlement. This is why droughts are so damaging to home foundations.

Drought will cause clay soils to shrink in volume and require homeowners to contract for foundation repair

Drought Map of USA – May 20, 2014

For more information about droughts and foundation repair please return to the home page.

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What is Foundation Failure ?

Posted by on May 19, 2014 in Learn | 0 comments

What is the definition of Foundation Failure?

Our definition of “foundation failure” is when one of the following is present:

1) Doors and Windows are Non-Functional

2) Plumbing Damage

3) Severe and Progressive Damage to Framing

4) Structural Integrity at Risk

Foundation movement can have very adverse effects on chimneys. Foundation repair and support is needed.

This chimney has separated from the house framing and brick wall. The gap is more than 3 inches.

Most of the damage that is seen by homeowners is damage to sheetrock (interior walls) and brick walls (exterior walls). For the most part, this type of damage is cosmetic and the structural integrity of the house is not at risk. However, there are many cases where the foundation’s movement has caused much more severe damage. Let’s take a closer look at these symptoms of a moving foundation.

Doors and Windows are Non-Functional

If your primary front or back door can no longer be opened then it is non-functional and the homeowner has lost the use of part of the house. If the windows stick and can no longer be opened then they are also non-functional. These are common symptoms when a concrete slab foundation has cracked and part of the foundation is higher than the other part.

Plumbing Damage

Newer sewer and drain pipes are almost always made of PVC which has some flexibility. Older sewer and drain pipes are iron or concrete and have less flexibility. If the soil under the home’s foundation is moving (expanding and contracting) then the pipes can be broken causing an under slab leak – which should be repaired as soon as possible to avoid further soil movement and foundation damage.

Severe and Progressive Damage to Framing

When brick walls separate from the wood framing of the house it becomes serious. When brick walls separate from window frame it is also serious. Movement at the base of the house can be “magnified” at the top of the house. Separation of roof joists, rafters, and ridges can be a very serious issue in some houses where there has been significant foundation settlement or uplift.

Structural Integrity

As stated earlier, most foundation problems do not jeopardize the structural integrity of the home. However, in some cases the structural integrity of the home is at risk. Chimneys can and have fallen to the ground and taken some of the brick wall and framing too. Roofs can literally “split open” if the foundation movement is significant. The framing of the house can sag due to foundation deflection.

So it is always a good idea to have an expert evaluate your home and its concrete foundation if you see warning signs of foundation failure.

Oh, by the way, did you see our page on “Monumental Foundation Failure?” – a 12 story condo building fell to the ground.  You can find the link under “Warning Signs.”

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