Common Foundation Failures


Sewer lines can fail for many reasons:

  • The most common reason is that the materials used to make the sewer pipes were substandard. Cast Iron, Clay, and Orangeburg sewer lines are rigid and not forgiving. When the soil they are embedded in and the structure they are connected to heaves and drops they fracture under the pressure.
  • Another issue with these materials is that Cast Iron, Clay, and Orangeburg corrode and deteriorate over time.
  • Flaws in sewer line material and design are not detected during the construction and development of the slab and property. Some houses and buildings end up with a faulty sewer systems from the start.
  • Vegetation - A very small leak in a sewer line attracts the roots of plants and trees. These roots can cause root intrusion resulting in extensive and expensive damage to both the sewer line and the foundation.
  • The stability of your foundation is another factor that can cause sewer line issues. A shifting foundation can break a sewer line causing a leak and in turn, the leak can further damage the foundation.

For more information about sewer lines, see our blog post here.

Pier & Beam Skirting

Pier & Beam Foundations include a crawlspace beneath the structure. This crawlspace can serve as a disadvantage to the homeowner if left exposed. Open crawlspaces can attract moisture, mold, rodents, and animals seeking shelter. To enclose the crawlspace wire mesh and stucco is used to create a barrier wall between the crawlspace and the exterior space.

How to Keep Your Crawlspace Dry
Pier & Beam Foundations sometimes have exposed or poorly covered crawlspaces. This can cause moisture during heavy rain to accumulate and remain for long periods of time. In order to keep your crawlspace dry it is reccommended to install proper skirting with adequate ventilation. In extreme cases a humidistat fan must be installed.

For more information about Pier & Beam Skirting, see our blog post here.

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Water Line and Sewer

Leaks are by far the greatest cause of slab foundation failure. Water line leaks can contribute a large quantity of water over a short time. A very small leak in a Water line embedded in a slab is usually not heard or noticed. However over time, it can become a substantial threat that can exist for years before being detected. Often, the existence of a leak is only suspected or confirmed as a result of foundation failure. Upheaval can occur quickly and cause extensive damage. It has been recorded that as little as six drops of water per hour over 12 months can heave a slab foundation 1 inch. Statistical data indicates that over 70% of all slab foundation failures are caused by either water line or sewer leaks.

Seasonal Rain and Expansive Soil

Seasonal rain alone is not necessarily a threat to foundations due to the mere presence of the foundation itself. The foundation and its structure isolates the foundation bearing soil from contact with the rain. However, the combination of expansive soil and water is a common cause of slab foundation failure in Central Texas. The areas of most expansive soils include Austin, San Antonio, Waco, Dallas, and Fort Worth. In Central Texas, we go through cycles of very dry and very wet seasons. This results in slab settlement followed by upheaval. This continuous cycle might lead one to assume that soil settlement (periods of dry weather) would be completely restored by upheaval (periods of wet weather). However, studies have found that each wet cycle leaves the foundation short of its original grade. This combination of conditions is unique to Central Texas.

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Trees and Vegetation

It is important to note that tree roots that receive adequate water would not seek the inhospitable soil conditions beneath a foundation. Monitoring precipitation and watering when needed will help prevent tree roots from migrating under foundations. That said, over watering is another common catalyst to foundation failure. Often homeowners will water a garden at one area of the yard (where a garden might be located) and not the entire perimeter of the slab. This may cause one side or one corner of the slab to heave and/or crack while the other areas of the slab remains in place.

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Construction defects

Construction defects (slab foundations) include: Poor construction of the slab, Utility leaks beneath the foundation, pouring the slab foundation off grade, faulty slab design, construction add-on slabs(for additions), faulty exterior grade (soil /landscaping), negligent of maintenance, faulty slab design. (For more information about Pier & Beam Skirting, see our blog dated … titled…)

For more information about Pier & Beam Skirting, see our blog post here.

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Pier & Beam Foundation Failure

Pier & Beam foundation problems happen on the same frequency as slab foundations but the degree and cost of the problem is much less.

Excessive Weight on Floor Joists & Wood Beams

Excessive weight that has been placed above floor joists in an area that is not supported by piers will cause distortion of floor joists and wood beams. Good examples of excessive weight are the tile and mortar used in bathroom designs during the 1940s – 1970s. Prolonged distortion of floor joists and wood beams on the interior of the home will make leveling difficult but not impossible. However, compromise is required.

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Faulty Placement or Design of Piers

In some cases the materials used to support the wood sub structure is substandard and most often made of Cedar.Wood piers are subject to deterioration as a result of decay and insect infestation. Another example of substandard pier is the cinderblock with failing (crumbling) mortar. Other examples of a faulty design and failure of a piers or pier system include; off-center pier locations, tilted piers and standing water around piers causing heave.