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What Is Underpinning?: Top Residential Foundation Repair Method

underpinning foundation

A stable foundation is key for a home, yet is often overlooked during annual home maintenance. Foundation problems can go unnoticed, increasing over time and leading to a variety of issues, including foundation problems such as pest invasions, mold growth, increased electric bills, and broken plumbing.

These problems commonly arise from soil changes underneath the home. If the soil shifts or becomes unstable, the home’s foundation may crack or suffer from settlement. However, a process called underpinning can restore stability to the foundation. More on underpinning follows.

What Is Underpinning? 

Underpinning is the process used to repair or strengthen an existing house or a building. When contractors begin with underpinning, first they dig out the soil underneath the foundation. However, the excavated soils are not moved all at once, but in stages so it doesn’t come to structural problems. The whole process should be completed by professionals since even the tiniest miscalculations can result in disaster. Structural engineers need to calculate how much soil should be excavated until stable soil is finally reached. During the underpinning process, one layer of soil will be removed, replaced with an underpinning material, and only then the next layer will be removed. This process is repeated several times until stability is achieved. 

Reasons for Underpinning 

When the usage of the structure has changed, sometimes the foundation needs to be reinforced, which requires an underpinning process. Sometimes the need for this process rises due to the changing properties of the soil supporting the foundation. There are times when the stability of the soil was mischaracterized during the construction of the structure, so now the homeowners need to strengthen the settling foundation. In addition, if owners of the house wish to expand their home and add another story, they need to reinforce the foundation first, otherwise, the structural stability of the entire house could be compromised. Another reason for underpinning is changes in the soil caused by a natural disaster such as an earthquake. 

Types of Underpinning 

Sometimes, reinforcing the foundation is a necessity. When it comes to the underpinning process, there are various types builders use these days. One of the most reliable is the pile or pier method. If your home in Michigan currently sits on unstable soils but there is better soil a layer below, albeit at a significant depth, the pile method is recommended. During this process, the foundation piers are evenly distributed along the foundation. Their purpose is to lift it and transfer the load from the foundation to the piers. 

There are several foundation pier methods that can be used to strengthen your foundation and ensure the stability of your home. 

  • Push piers: One of the most popular types of piers is push piers. These are driven into the ground and their main purpose is to permanently stabilize the foundation. They also can potentially lift it back towards its original position. They are made from galvanized steel, so you don’t have to worry about them rusting over time due to the moisture in the ground. 
  • Helical piers: Helical piers are similar to push piers, except they are screwed into the ground instead of being driven into the ground. They are ideal for lighter structures like porches and chimneys. 
  • Slab piers: Slab piers are designed to support a slab foundation and prevent it from settling. 
foundation pier bracket

Temporary Underpinning Solutions 

If there aren’t any significant issues with your foundation, your contractor might recommend some of the temporary underpinning solutions. Keep in mind that these are not permanent solutions. 

  • Concrete underpinning: With concrete underpinning, the soil underneath the foundation will be excavated and a new layer of concrete will be poured under the existing footings. The idea behind the process is to lower the footing so it can stand on more supportive soil. After the concrete has dried, the left gaps will be filled with the excavated soil. However, this method doesn’t exactly address the unstable soil. 
  • Concrete piers: Concrete piers are concrete cylinders connected with a wire. They are driven into the soil, but since nothing is guiding them, they cannot go deep into the ground, which might be a problem. 

Get Durable Underpinning Solutions Today!

helical pier

Fixing your problem for good is always a better option, and this way you will be at ease knowing that your foundation has been properly reinforced.

If you have a problem with the settling foundation, contact professionals at FSM to schedule a free inspection and repair estimate. Our inspector can assess the situation and recommend the best way to reinforce your foundation. 

Underpinning FAQs

Generally, they require no maintenance, but regular foundation inspections are advisable to detect any potential issues early. 

Homeowner’s insurance typically does not cover foundation settlement, but it’s best to consult your policy or speak with your insurance agent for specifics.

When presented with several foundation repair solutions, it’s easy to get overwhelmed before making your decision. We’re happy to offer our expertise to help guide you to the right decision for your home. Let’s take a closer look into all the foundation repair solutions that we have to offer below. 

A Note on Wall Anchors 

Though wall anchors are extremely useful in bracing your basement walls against any kind of damage, some homes might not have the space around their yard for this solution. Each anchor will be placed in compact soil buried deep around your home. Each anchor is then braced against your basement wall to prevent any outside pressures or other threats from causing it to bow in. 

Wall anchors essentially block out this movement altogether. Our experts can also slowly tighten these anchors over time to ensure that your basement walls will straighten out and close any cracks that have formed. You will not have to worry about any new cracks forming along your wall either. 

Carbon Fiber Wall Straps and I-Beam Support Braces 

If you do not have enough space in your yard for wall anchors, it might be best to install either carbon fiber wall straps or I-beam support braces in your basement instead. These will work just as well to brace your basement walls and foundation against any sort of damage. You might not know which of the two solutions is best for your basement. 

While both are tough solutions that can brace your basement walls against anything, you might simply like the look of one over the other. Carbon fiber wall straps are thinner straps that can easily be painted over if you want to. Our I-beams will obviously stick out far more, but you might be reassured by their overall rust-resistant protection. 

Leah Leitow

Leah Leitow

Content Writer

Leah is a Content Writer for Groundworks with nearly ten years of experience working in the foundation repair industry. Her experience ranges from working with homeowners to find the right solution to training inspectors and staff. In her background as a Michigan journalist, she gained invaluable insight into people's lives throughout our state. Leah lives in metro Detroit with her husband and two sons.

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