1. What is Foundation Repair
The term “Foundation Repair” is misleading; the word “repair” typically denotes that something
is broken and needs fixing. Typically speaking, what takes place when a foundation fails is that it
actually settles beyond an acceptable point, causing components of the superstructure to
become distressed or misaligned. This type of structural movement can and does lead to failures
of the superstructure components that can ultimately lead to total structure failure or collapse.
Now, total failure is a very extreme circumstance and is in no way common. More common
occurrences are damage to cosmetic veneers such as brick or stone, flooring such as ceramic
tiles, sheetrock, door frames and most commonly doors that do not fit in their frames and fail to
The fix: Foundation Repair solutions can vary depending on the type of structure afflicted by
movement. For your structures built on a concrete slab on grade the typical repair will consist of
some kind of piling, or pier for short. Once the needed pilings are installed the structure can be
vertically moved to appropriate the surface levels as close to original elevation as possible.
Should the afflicted structure be of Pier & Beam or Block & Base construction (having a crawl
space under the house) the typical repair would consist of leveling the structure over the
existing block supports, with the addition or replacement of wooden components and or
concrete block materials.
In short, the term “Foundation Repair” in most cases should be called foundation leveling via
underpinning. “Foundation Repair” isn’t quite as much of a mouthful and generally covers the
idea that something is wrong and needs attention; but the use of the term has created some
misconceptions within the world of homeownership and the industry.
Cracked slabs: Such a dramatically overused term used to oversimplify the issues and relay the
message that attention needs to be paid to the deficiency at hand. Check any engineering
manual written to cover concrete, every piece of concrete in the world has a crack of some form
or another in it; the Hoover Dam has cracks in it, yet it continues to this day to hold an
enormous amount of water that if released would cause catastrophe on an unimaginable scale.
Yes, your concrete slab home has cracks in the foundation; no, those cracks are in no way an
indication that the structure will collapse with you and your loved ones inside of it.
Most concrete cracks in the drying stages and in order to begin to understand why we need to
get back to our high school science basics. The first question is: what happens when something
dries? Much like wet laundry, the drying of concrete is simply the evaporation of water. That
evaporation of water causes a chemical change in the cement that causes it to become very
dense and rigid, making it a suitable material to build structures on or out of. But what happens
to the volume of space occupied by the water that was once there? Much like a dish sponge
when left wet on the kitchen sink, the void doesn’t remain, rather the overall volume of the
piece of concrete is reduced by the volume of water removed in the drying process. Just like a
piece of cheesecake left out overnight, the shrinking of the concrete material results in small
fractures in the surface that may alarm someone none the wiser. These shrinkage cracks are not
in any way a structural deficiency and should cause zero worry, it’s all part of the process.
Foundation repair relies on a couple of different factors, let’s discuss this regarding a concrete
slab on grade built to residential specifications. Factor number one is density, if the foundation
cannot withstand a compressive force sufficient to raise the structure, the repair will not
function. Second is stiffness or rigidity; if the concrete does not possess the proper stiffness it
may want to fold, for lack of better term, between the points of support. Support points can be
looked at as both the point where the foundation is supported by the pilings and the point
where the foundation is naturally resting on the soil. Most foundation repairs are partial
underpinnings where the entire slab is not afflicted by movement. A common example can be
that the right-hand side of the structure can have experienced settlement whereas the left-hand
side is as it was the day it was built. Most single-family residences are going to have a sufficient
foundation under the home and should withstand a repair job without much issue. Should the
foundation be too brittle or maybe too thin to provide the necessary stiffness, a proper solution
should be entertained from either your foundation repair contractor or an engineer.
Pressed Pilings: Here comes the biggest controversy in the industry. Do pressed pilings actually
work? The short answer is yes, they absolutely work; but not for the reasons you might think.
Let’s ask the question what tool is better, a hammer or a screwdriver? Both are used to secure
fasteners to wood, but neither one is better than the other; they simply perform different tasks
to ultimately perform the same end function of installing a fastener. The same argument can be
had for the variety of different piling methods. Pressed pilings only work when the immediate
load of the structure at the installation site of a particular piling is great enough to overcome the
resistance that the soil will apply to the piling segment as it is driven into the earth. Fortunately
for us, most single-family residences possess the proper immediate load to install the industry
accepted segmented pressed pilings without boringly reliable results.
Understanding what we just discussed above regarding pressed pilings installed under a slab on
grade foundation we can move on to how a pressed piling works. Let’s talk table legs for a
moment, the way a table leg functions is that it transfers the load of that corner of the table to
the floor. The only way this load can be supported is if the load bearing substance (in this
example the floor) must withstand the increased pressures applied by the reduced surface area
of the table leg at its point of contact with the floor. Fortunately, the floor in your home is
designed to withstand the weight of the entire superstructure and therefore will indefinitely
support your dining room table. This can also apply to pressed pilings but only in very specific
circumstances. Some type of load bearing strata needs to be available within the depths capable
of your piling which in speaking regarding sites located in Texas, can be found where more
accessible large deposits of limestone can serve as the kitchen floor as in the above example.
More commonly, the pressed pilings act as a friction piling, where the resistance to support the
home comes from the applied friction of the soil being imposed to the entire surface area of the
pile shaft as it is driven into the earth. This friction applied to the piling only increases as the pile
is driven deeper into the ground, the two most common factors that increase friction are the
added density of the soil due to compaction and the increase in applied surface area due to
additional segments of the pile being installed. The more surface area applied the better the
frictional coefficient will be, this is why drag racing cars use slick tires in leu of tires designed to
perform in the rain.