By Martin Dawson
The Pressed Piling method of foundation repair evolved in the 1980s in an effort to reduce the cost of repairing foundations. However, it has been widely used for over 20 years and it has some disadvantages. We will discuss both the advantages and disadvantages in this article.
The cause of almost all foundation problems in the southern United States is the presence of expansive soils. Foundations rest on top of these soils which provide the ultimate support for the foundation. The problem is that portions of the soil under the foundation will shrink and swell. When the soil absorbs large volumes of water it creates an ‘uplift’ effect under one portion of the foundation. This uplift can crack the rigid concrete foundation and cause damage throughout the building structure such as cracked interior walls and jammed doors. Similarly, when a portion of the soil under the foundation loses a significant amount of water due to evaporation or withdrawal by tree roots, the foundation will ‘fall’ or collapse because it has lost some of its underlying support. Typically these problem areas are around the perimeter of the foundation because the moisture content of the soil under the interior portion of the foundation usually remains relatively stable. However, soil movement and plumbing leaks can also cause problems with interior portions of the foundation.
The advantages of the Pressed Piling method of foundation repair are its short total job time and lower cost. This method uses a series of precast concrete cylinders that are pushed into the soil using the weight of the home or commercial building. Since there is no poured concrete or curing time, this method can usually be completed in one or two days. And this method generally uses less labor and concrete than other methods.
The first disadvantage of the Pressed Piling method of foundation repair is the potential for misalignment of the concrete piles. There is no method to verify if the piles have been pushed into a straight and vertical column. Past history has shown that the piles can hit a rock, tree root, or other obstruction and become misaligned. Or the pushed piles can simply ‘wander’ off at an angle. In addition, the NON-reinforced concrete pressed piles can crack and break and cause misalignment. If the pressed piles are misaligned then their ability to provide support to the foundation is jeopardized.
Another disadvantage of the Pressed Piling method of foundation repair is that the pushed piles can reach a point where they can not be pushed any further. The weight of the home or building structure is not enough to push the piles any deeper and this is called the refusal point. The force required to push the piles past the refusal point is greater than the weight of the home or building. This is a critical point and all attempts to push piles deeper should cease immediately. The work crew could potentially cause damage to the foundation and building if they continue.
Another disadvantage of the pressed piling method of foundation repair is that the pressed piles are not connected in any manner and they are subject to the lateral and vertical forces of soil movement. Soil movement can cause vertical and horizontal misalignment of the concrete piles. Expansive soils will repeatedly shrink and swell during a single year. After several years (or sooner) the unconnected piles can become horizontally misaligned and / or lose their vertical integrity. If the unconnected concrete piles become misaligned over time, then they may lose their ability to support the foundation.
Because the pressed piling method of foundation repair was designed to be a low cost alternative, a soil test, or review of a soil test by an engineer, is a rarity. Therefore the repair company does not know how deep they must push the piles to reach stable soil or bedrock. If the piles do not reach stable soil or bedrock then they may not provide support in the long term.
In sum, the pressed piling method of foundation repair has significant disadvantages. The best ‘insurance’ is to select an experienced foundation repair company with many years of history and demand a warranty or lifetime service agreement. Be wary of arbitration agreements and clauses that require the customer to forfeit some of his / her legal rights.
About the Author: Martin Dawson is the co-founder of
Dawson Foundation Repair
headquartered in Houston, Texas. He is a leading authority on repairing failed commercial and home foundations using the time tested and thoroughly researched drilled Bell Bottom Pier method. His company has serviced Texas since 1984 and been a member of the Better Business Bureau and the Foundation Repair Association.