Sister Walls

Many homes in Pasadena, California, and other parts of San Gabriel, are lined with homes built upon brick foundations. These foundations were around as early as 1890 or even earlier (and some, of course, more recently). Masonry foundations, like traditional red brick chimneys, lack rebar reinforcement. Over time, environmental influences, such as rainwater and active fault lines, begin to weigh down upon them. That’s when they begin to fail. And they do so faster and more vehemently than traditional concrete foundations.

There are a few notable solutions to stabilize these old brick supports, one of which is referred to as a sister foundation, which is the process of erecting a concrete wall reinforced with steel adjacent to the old brick wall. Once installed, it upholds the integrity of the support the original wall was once young enough to endure. (Click here for more detailed information to see whether sister walls are right for you.)

The term “sister” is used in other fields other than foundation repair. In electrical engineering, for instance, it can describe a unit designed to offset heavy influx of electrical current in a closed-circuit system. When we think about the importance of this term universally, we suspect that it gets its name and inherent meaning from the traditional nuclear family. A sister in this case is the daughter or sister who adds significant value to her parents and siblings. When we reapply it to the support needed for brick foundations, the sister wall adds extra support for those homes which are in jeopardy of severe structural damage.

In the event of a major earthquake here in Southern California, a failing brick foundation may lead to a completely damaged home. Keeping in mind that many of these brick foundations are old by nature, they have managed to survive through numerous earthquakes as it is. As they continue to absorb tectonic pressure from the earth, any additional stress from the environment, such as torrential rainfall, may easily serve to knock the house of cards over.

Until then, it is possible for your home to experience severe cracking and shifting, which will cause doors and windows ineffective to open and close with proper ease, while floors will squeak, and your walls become noticeably unstable. Simply put, a failing brick foundation is both unsafe, and it will also incur very costly repairs, especially if the long-term solution is placed on the back-burner.

Other foundations that commonly need sister walls include river rock and stone foundations. Like their names suggest, they are made entirely out of naturally found rocks and stones. During construction, they are piled and “glued” together with mortar, which may loosen strength overtime due to seismic activity. Many engineers agree that replenishing the mortar is a good short-term solution. Weinstein Retrofitting Systems, and the engineers we work closely with, believes that adding sister support is one of the most structurally practical ways to go. The new sister wall typically adds another 75 years of structural concrete strength under today’s building codes, providing you and your family peace of mind.