What You Need to Know About Underpinning a House

A home's foundation may eventually need underpinning, or an added layer of support, in order to support the weight of the home and protect the foundation from damage and cracking. It may also need underpinning to repair this damage. Consider a few important factors about underpinning and when it may be needed so you know if you should discuss this option with a contractor when it comes to your home's foundation.

1. Understanding subsidence

Subsidence refers to the soil of your property actually pulling away from the home's foundation. You may notice a trench or gap between the foundation's slab and your property. Subsidence is often caused by drains or tree roots that are pulling the soil away from the home and in turn, not giving it proper support. This subsidence is one cause of a home's foundation needing underpinning, as soil helps to support the weight of a home. When it pulls away from the home, the foundation may not be strong enough.

2. Looking for cracks

One common sign that your home's foundation needs underpinning is when there are cracks on the inside basement walls or on the outer walls of the foundation. However, note that if you have added stucco or any type of plaster to the interior walls, this material itself may show minor cracks. These are not dangerous as it's not the foundation itself that is cracking but the stucco or plaster. Look for cracks in the concrete itself, inside or outside the slab, in order to determine if your home's foundation needs underpinning. You may also note cracks around doorframes or window frames, or that doors seem to lean and not close properly. These are signs that the home's weight has shifted and the foundation is damaged.

3. What is underpinning?

The word "underpinning" may make you think that pins are added to the foundation of your home, but the word refers to adding to the foundation to increase its depth or overall strength. One method does involve screw pins and brackets that are attached to the home to help keep it supported. Another method is called a mass pour, which means adding more concrete around the foundation's slab to help support the home's weight. The type of underpinning you need to have done for your home will depend on the amount of support it needs and the damage it's suffered. If you notice large cracks in the home's foundation or the subsidence of soil, discuss your options for underpinning with a contractor so your home is protected.