Looking for information about jacking up a house for foundation repair? If so, don’t hit that back button because you’re on the right page. In this article, we’re going to review what the term “house jacking” means, how it’s done, what causes foundation problems, and much more.
What Is House Jacking?
House jacking – also known as house leveling, foundation leveling, and underpinning – is a technique foundation repair contractors use to lift and strengthen an existing foundation experiencing a phenomenon called “differential settlement”.
What Is Differential Settlement And What Causes It?
While all foundations settle into the ground slightly after they’re built – they are pretty heavy, after all – as long as the settlement is uniform, this usually isn’t a cause for concern. The problem is differential settlement, or when a foundation settles into the ground unevenly. The best way to understand the difference between uniform and differential settlement is through an illustration:
Differential settlement places a lot of stress on a foundation, and if it isn’t corrected via house jacking, it will cause severe structural damage.
So what causes differential settlement?
Some common causes of differential foundation settlement include, but aren’t limited to, the following:
- Expansive soil – Expansive soil contains a lot of clay; when exposed to moisture, it swells and increases in volume. Conversely, when the soil releases moisture and dries out, it shrinks and decreases in volume. This continuous cycle of swelling and shrinking can cause significant damage to structures built on top of expansive soil, leading to differential settlement.
- Erosion-prone soil – Some types of soil are prone to erosion; over time, this can cause voids to form under the foundation. If the foundation then settles into these voids, differential settlement will result.
- Poor construction practices – Soil must be compacted before anything gets built on it. The compaction process involves using heavy machinery, such as rollers, to remove air pockets in the soil, making the ground more stable and uniform. Failure to properly compact the soil can lead to differential settlement.
- Natural disasters – We probably don’t need to explain how natural disasters, like earthquakes, floods, tornados, etc., can lead to differential settlement.
- Tree roots – Tree roots can also cause differential foundation settlement. Two ways this can happen are large tree roots pushing up on a foundation and tree roots “drinking” moisture from the soil, dehydrating it, and causing the formation of voids under the foundation.
Signs Of Differential Settlement
Homeowners need to be able to spot the signs of differential settlement early when it’s less expensive to repair. Here are some things to look out for:
- Cracks in walls, floors, and ceilings – These cracks might be horizontal, diagonal, or vertical. You might see a crack across the ceiling and down the wall. Cracks from the corners of doors and windows are also a common sign of differential settlement.
- Doors and windows that stick or don’t close properly – This happens because when the foundation settles into the ground unevenly, it throws everything out of plumb.
- Stair step cracks in brick or masonry – This is a sure sign the foundation has moved.
- Uneven floors – These might be barely noticeable.
- Gaps between walls and ceilings or between walls and floors – These don’t necessarily need to be large separations. They might be very slight.
- Leaning porch or chimney – The problem might be with the foundation under the porch or chimney, or it might be a problem with the house’s foundation itself.
- Torn wallpaper – This might be a sign the wall behind the wallpaper is cracked.
If you see any of the above or anything else that strikes you as suspicious, contact a foundation repair contractor or structural engineer right away and ask for a foundation evaluation. Don’t delay. Foundation issues worsen over time; if you wait, you’ll pay more for the repair.
For more information, see Foundation Settlement.
Jacking Up A House Is A Foundation Repair To Correct Differential Settlement
Jacking up a house – also known as foundation underpinning – is a common foundation repair technique used to correct differential settlement.
Jacking up a house (i.e., underpinning) involves installing piers (push, helical, slab, or drilled concrete) under the foundation to stabilize it. This technique can be used for any foundation, including slab foundations, pier and beam foundations, and basement foundations.
Types Of Piers Used For Jacking Up A House (i.e., Underpinning)
Jacking up a house for foundation repair is done using push piers, helical piers, drilled concrete piers, and slab piers.
Heavy-duty steel push piers are driven into the soil beneath a home’s foundation using the weight of the house and hydraulic pressure until they reach a stable soil layer. Once they’re in place, a synchronized hydraulic lifting system raises the house to maximum practical level or as much as possible without damaging the foundation.
Helical piers have a spiral shape that allows them to be turned into the ground until they reach the necessary torque and depth specified by a geotechnical engineer. Once they’re in place, a synchronized hydraulic lifting system raises the foundation.
Drilled concrete piers
Drilled concrete piers involve drilling holes in the ground and filling it with reinforced concrete. The process is labor intensive, but the resulting piers are very strong.
Slab piers are push or helical piers installed through holes drilled into the slab.
How Is House Jacking Done?
Underpinning using push piers is a common repair solution for foundations experiencing differential settlement. The general installation process is as follows:
- The first step is to excavate the soil surrounding the foundation to gain access to the footing and prepare the area for pier installation.
- Heavy-duty steel brackets are attached to the foundation.
- The steel push piers are driven through the brackets and into the soil using hydraulic equipment until they reach the load-bearing strata.
- After the piers are installed, they’re load tested to ensure they can support the foundation’s weight and the structure above it.
- Following the successful load testing, the piers are connected to the foundation footing, transferring the weight of the foundation to the push pier system.
- After the piers have been installed and connected, the excavated soil is replaced.
Check out how House Jacking is done in our video here!
Underpinning using push piers is a highly effective method of repairing foundation settlement problems. It’s cost-effective and can be completed quickly without significant disruption to the property.
Jacking Up A House Is Not A DIY Repair
Jacking up a house is not a DIY repair for several reasons. Firstly, it requires specialized equipment such as hydraulic jacks and the piers themselves. It also requires a thorough understanding of the house’s foundation, structural components, etc. Trying to jack up a house without the necessary equipment or knowledge can result in severe structural damage. It’s also crucial to address the underlying cause of the differential settlement to prevent future damage and ensure the long-term stability of the foundation.
Can I Live In My House While It’s Being Repaired?
In most cases, you can live in your house while it’s being repaired. Rarely does a homeowner need to vacate their house while it’s being underpinned. However, there will be some noise and a bit of dust. However, it shouldn’t disrupt your daily routine that much.
How Much Does House Jacking Cost?
Many factors can affect the cost of house jacking, including the size of the house, the type of foundation, the extent of the damage, your geographical location, and the chosen repair solution. Here in California, as of August 2023, the cost to underpin a foundation generally ranges from 25K to 35K. Each home is different as the problem of settlement is typically never the same. While this might seem like a lot of money, the cost of not fixing a foundation can be far greater in the long run.
If you’re concerned your home might have a foundation problem, contact Bay Area Underpinning today to schedule a foundation evaluation. If we find a problem, we’ll give you a repair estimate. We serve all of Northern California.