Underpinning a home refers to adding large pins under or around a home's foundation, in order to brace up that foundation and make a home level again. Underpinning is just one type of foundation repair available; a home built on wood blocks may need re-stumping, and adding an extra layer of concrete around a home's foundation can keep cracks and other damage from getting worse. However, underpinning may be used for concrete slabs that have already cracked so severely that the home is no longer level and even. If you know your home's foundation needs underpinning, note a few questions you might want answered.
Is underpinning permanent?
The pins used for underpinning a home are very strong and durable and are meant to hold up the weight of a home. A contractor will note the best location for them and how many pins to use for maximum protection of your home's foundation, given its weight and the extent of the damage.
While underpinning is a long-term solution, note that changing soil conditions and other such causes can mean that you might need to have the home underpinned again or the foundation repaired again, but typically not for quite some time after the pins are installed. Underpinning may last for decades, depending on the outside factors that affect your home's foundation. Your contractor can tell you how long you might expect your underpinning job in particular to last and if you have options for protecting your home's foundation even more, such as adding a layer of plaster to exposed areas of the foundation or installing a retaining wall to help control the moisture in your soil.
Our home was built with a strong foundation; why is it now damaged?
A home's foundation can be damaged by too much moisture in the soil; this can cause the soil to expand and put pressure on the foundation. Pressure can allow cracks to form and these may get bigger over the years. Holding moisture next to the foundation may also cause it to get soft and crack.
On the other hand, dry soil may settle and pull away from the home and voids form between the foundation and the soil. These voids don't give the foundation the support it needs from soil, and it may start to crack. Small earthquakes that happen deep underground and which you may not have even noticed may have caused cracks in your home's foundation. Talk to your contractor about potential causes of this damage so you can take steps to avoid it in the future.