Steel and pressed concrete pilings/piers are the most commonly use foundation underpinning repair methods in North Texas.
Except in areas of shallow rock, the goal with underpinning should always be to drive it deep enough into the earth so as not to be effected by seasonal changes in moisture. In North Texas that depth is generally recognized by engineers as around 12 feet.
Steel piers are the preferred method for most long term foundation repairs. Steel piers are driven in sections to either load bearing strata or rock. Depths may be as great as 70 feet.
Pressed concrete pilings are a lower cost alternative to steel piers. Concrete cylinders are driven to refusal in clay soil. Refusal in the Dallas Fort Worth area typically occurs at a depth of 8 to 15 feet, dependent upon soil moisture and weight of the foundation. If the installer does not use water injection, depth may be somewhat more limited.
If you can afford the cost differential, always choose steel. To learn more about the two systems, click here. You will find a very detailed comparison of the systems.
Straight steel pier driven deep to load bearing strata, typically rock. Illustration courtesy Granite Foundation Repair
Pressed concrete cylinders are driven to load bearing strata. Typically compressed clay. Illustration courtesy Granite Foundation Repair.