SABER is company that offers a lot of services having to do with concrete repair and slab leveling including residential foundations.
If you are checking out foundation repair companies and have questions about about methods of repair and steel piers in particular the SABER website may be of help to you
Their website describes two of the more common types of steel piers on the market today: resistance and helical piers.
“There are generally two types of steel piers used for underpinning foundations. Resistance and helical. Both have their advantages and best uses.
Resistance piers are hydraulically pushed or driven straight down through the soil using the weight of the structure as a counter balance. The piers are pushed down until the end reaches a layer of soil hard enough to support the structure.
Resistance piers are best suited for structures that need to be raised or have very heavy load requirements.
Helical Piers are hydraulically twisted or turned into the soil much like a corkscrew. The piers contain one or more “flights” that pull the pier into the soil. These piers are screwed down until they reach soil that is thick enough to support the desired result. Since they are screwed in, they cannot be pushed or pulled out. They can be used to either support a
structure or to keep a structure from coming away from the soil such as a retaining wall or a home on a hillside. These types of piers can also be used as pre-construction piers to prevent future foundation failure.
Both resistance and helical piers are made in a variety of configurations to support a variety of structures. The proper selection of the proper pier is an important calculation the service contractor must make prior to quoting a job.”
If you’ve been following along, you may remember the engineer who inspected my foundation recommended using either steel pipe or drilled concrete piers to level my slab. Steel pipe would fall into the resistance pier category.
As I understand it, helical piers are most useful if your slab is on a slope or hillside because of the way they can grab soil at an angle using the “flights.”