Foundation cracks worry a lot of people. Home inspectors may tell you that they need to be repaired, and to consult with foundation repair contractors/residential foundation contractors. Home buyers may see problems that call for your foundation fixing but walk away from a potential transaction or ask for a reduction in the sales price. Truth is, most foundations have cracks. It is the type, size, and orientation of a crack(s) that determine whether or not there may be a problem.
From the moment concrete is placed, it begins to shrink via the hydration process. Extensive research has been conducted to evaluate why and where concrete tends to crack. As a result, several standards have been put into place to reduce, eliminate, or control the locations of cracking.
There are several external factors such as temperature (both ambient and concrete mix), water content, humidity, and placement practices that all play a role in how concrete performs.
There are two common means of control done by our residential foundation contractors. The first, Expansion Joints, are designed to permit expansion and contraction of concrete masses. On the other hand, Control Joints are saw cuts or tooled joints in concrete sections to allow it to crack at specified locations. The addition of reinforcement in the pour, such as rebar, will also help curtail cracking.
However, in the end, most concrete pours crack during the curing process. The American Concrete Institute (ACI) spells out the technical aspects here, but the California Department of Transportation adopted an easier to read specification for concrete shrinkage. .05% - .08% for every 12’ feet. This works out to about the width of a dime every 12’.
“Hairline”, or small cracks, are typical in most foundations. They generally are vertical and are not offset. That is to say, that one side of the crack has not moved up or down, or in and out as opposed to the other side. They are also generally the same width from top to bottom. These types of cracks are generally considered normal and are usually of small concern. Water can get into these cracks, and if it freezes, can actually break off pieces of concrete making the crack bigger. The best way to address these cracks is to have residential foundation contractors seal them up with paint, caulk, or a variety of readily available sealers that will prevent water infiltration.
However, any crack wider than ¼” may be cause for concern and a need for fixing the foundation as it can allow for water infiltration. The type of crack is also important. Diagonal cracks & cracks that are wider on one end vs. the other may be a sign of movement. Cracks that are offset, or groups of several cracks are also likely a sign of distress. These types of cracks should be looked at by a professional to determine a cause and remediation. All structures settle over time. The purpose of a foundation is to allow the structure to settle as a unit at a slower rate. If you have foundation problems, you are likely to see interior sheetrock cracks, doors misaligned within the jamb, uneven floors, tile cracks, window frame separation, and even walls pulling away from the house.
These can be signs of water infiltration, movement or distress in your foundation.
In summary, concrete cracking can be the result of a poor batch of concrete, poor placement and/or curing methods, less than adequate installation of expansion and/or control joints, or the result of non-uniform foundation soils movement. Concrete cracking is generally classified as structural or non-structural. Structural cracking may require monitoring and potentially remediation, while non-structural cracking is mostly cosmetic in nature.
If you start to see threatening cracking in your foundation, give one of our residential foundation contractors a call at 775.284.1964 or send us an email! We will be happy to come out and take a look as your foundation crack repair experts!
445 Western Road