If your house is sinking, moving, or settling, it can mean serious damage to the foundation and may compromise the whole structural integrity of the building. If the soil around the house is not supporting the footing, you may need to consider a foundation repair work or underpinning. While the layman term is house lifting, the process is actually called underpinning or piering. The pier is also called a piling. There are several different types of piers to stabilize a home’s foundation. However, like waterproofing, there isn’t just one way that will solve the problem. The different underpinning methods all work to solve a foundation problem, but it is just a matter of figuring out which one is right for you.
There are four major systems commonly used for poured wall foundations with basements or crawlspaces:
1. Drilled Piers:
For this system, a deep hole is drilled and set with reinforced steel. Then the contractor fills the hole with concrete and ties the piers to the home or foundation. In a sense these piers work as a new concrete foundation.
2. Push Pier:
The Push Pier (Steel Pipe Piling) method uses the weight of the structure to push the piers into the ground until they hit a load-bearing level of the soil or bedrock. The pier is then capped off and permanently attached to the bottom of the foundation. This method is a simpler method in way of knowing it is successful just by installation. When the weight of the house is insufficient to drive the piers deeper, that’s evident they can support the home. They are typically used for heavier structures but also work well for single story homes.
3. Steel Helical Pier:
Helical piers are typically used to support a structure and not to lift it. Helical piers are turned into the ground like a corkscrew. Each pier has “flights,” or wings, which work to pull the pier into the soil. These flights also keep the pile in place after it is installed. Because helical piers don’t use the weight of the structure like push piers you can use them on very light structures, like a porch.
4. Segmented Concrete Pier:
This method uses precast concrete segments, usually manufactured cylinders, which are installed one by one on top of one another and pressed into the ground by hydraulically jacking against the underside of the existing structure. Like, push piers, the weight of the structure is used to create the reactive force that allows the pile segments to be driven into the soil. The segmented piles can be interconnected by steel bar(s), threaded rod, or a cable that runs through the center of each of the concrete segments. Other systems use epoxy or another adhesive to bond the segments together. The differences are determined by the manufacturers of the specific pier.
These four main systems can all be installed outside or inside the basement. If the system and equipment will fit inside the basement, it usually will save a day or two of labor to go through the basement floor instead of installing the system outside. Exterior piering typically means digging an eight- or nine-foot trench.
Contact us if you have any questions about foundation repair or house lifting.