What exactly is meant by the term Cripple Wall Foundation?

Do you live in the large and lovely house that sits atop an unstable cripple wall foundation? If so, then that’s a bummer. There are some houses that are more prone to earthquakes, which will shake up your home like a sloppy cocktail.

What exactly is meant by the term “Cripple Wall Foundation”?
A cripple wall is a type of raised foundation that is similar to post-and-pad and stem wall foundations. It is constructed out of wooden stud walls that range in height from 14 inches to 4 feet and is designed to produce a crawlspace between the subfloor of the house and the surrounding soil.

The wooden stud walls are supported by an exterior concrete foundation, with the majority of the support coming from compaction (which, as we will see in the following section, is a risky strategy in an area prone to earthquakes). Cripple walls are relics from the past and can be found in homes built prior to 1960 on hilly terrain that has a slope.

The term “cripple zone” refers to the portion of the house that is suspended above the slope, which is where the cripple walls are typically installed. This area is known as the cripple zone because it is the part of the structure that is most susceptible to damage in the event of seismic activity. Because of its name, you probably guessed correctly that the cripple wall is the first part of the house to buckle and, as its name suggests, is responsible for the home’s inability to stand.

Challenges Presented by Cripple Walls

As was mentioned earlier, the structural integrity of cripple walls is primarily determined by gravity and compression, specifically the load of the home that is placed on the cripple wall while it is sandwiched between the house and the cement foundation. Even though the cripple wall is tightly sandwiched between the house and the foundation, neither part of the structure is typically attached in an appropriate manner.

Therefore, in the event that there is an earthquake, crippled walls will break, rack, and/or slip out from in between the house and the foundation. This will cause that portion of the house to adhere to the principle of gravity and collapse (a technical Seismologist term).

Protecting Houses From the Effects of Earthquakes

How exactly does one fortify a cripple wall against the effects of seismic activity? When an earthquake strikes, it will shake and rock your house from side to side. The swaying motion of an unsecured cripple wall applies a significant amount of force to the structure of the cripple wall itself. The wood is significantly weakened as a result of the live load play and torque.

Therefore, the primary objective of securing a cripple wall is to restrict the movement that takes place as a result of an earthquake. This is typically accomplished through the installation of braces and bolts that strap the foundation, and cripple the wall, and home securely together.

When bracing and bolting a cripple wall, it may be necessary to use additional plywood to brace the interior of the stud walls in addition to securing framing/foundation anchors to connect the rim joist to the top of the stud wall. This is done in order to prevent the wall from falling down.

Upgrade the seismic protection of your crib wall.

You have learned through reading this article that a cripple wall is a type of raised foundation that is especially vulnerable to damage caused by earthquakes. You have also learned that bracing and bolting the foundation of your cripple wall is the most effective way to reduce the likelihood of further damage. You can get assistance with the Foundation Inspection Bell Gardens and repair services for the foundation of your home by contacting RLM Retrofit Foundation. You can call us at (800) 824-6699. You can count on us to provide you with premium quality service.

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