What is a reliable foundation repair method? With so many different foundation repair systems, it is difficult to know. There are many competing claims and a lot of hype in this unregulated, unlicensed industry. What is a person to do? Do you get steel piers or concrete piers? How far should they be spaced? How deep should they go?
Due to our clay soil and relatively shallow rock, there are a number of foundation repair methods that can be used in Dallas for foundation underpinning. They are not all created equal.
The list includes, and these are not in any order of preference:
Mud jacking – A cements slurry
Poured Concrete or Drilled Concrete Pier – A shaft 10-20 feet deep with rebar reinforced concrete
Straight Steel Piers – 3-inch steel driven to rock
Helical Steel Piers – Round 3 inch or square 1 ½ inch with a helical plate
Hybrid Concrete Pier with Steel Leader – Pressed concrete with a 2-4 foot steel leader
Pad and Block – Cement pad with blocks
Foam Injection – High tech form of mud jacking with urethane foam
Stapling – A method of connecting two slabs
Chemical Injection – Usage is to stabilize the soil under the house
Drainage Correction – For standing water problems
The leading pier systems in usage in Dallas Ft Worth are steel piers, poured concrete piers and pressed/precast concrete pilings. These systems stand out for providing reliable foundation repair.
For the Dallas area, which is clay overburden and relatively shallow, solid rock or shale, we strongly encourage customers to use Granite Steel piers. Straight steel is always driven to rock. The rock provides a stable platform to assure that the foundation will not continue to drop. Using the weight of the house, installation is verified when the house rises during the steel driving process. Installation equipment is relatively expensive.
Helical Steel Pier
Granite Foundation Repair augers round helical steel piers into the ground to specific depth and minimum rotational torque. Rotation torque effects the differential pressure of the auger system and is a reliable correlation to soil density. Soil density varies with depth, and may decrease as well as increase at different depths. The installation method is reliably used in those applications where the structure cannot be used to exert driving pressure. The choice of material is important. 3 inch helical pipe with a single or multiple 8-12 inch plates is ideal. 1 ½ inch square helicals, while in usage, are not well suited to supporting a structure. 1 ½ inch square rods were designed for tie back installations (such as Audion tower support wires), and we not designed for load bearing. Installation equipment and material are relatively expensive.
Pressed / Pre-cast Concrete Pilings
While sold under many trade names, the system consists of cylinders that are pressed into the ground using the weight of the foundation. Cylinders measure 6 inches in diameter and are 12 inches long. Granite uses water to facilitate a deep drive, which is essential to assure long term foundation support. Installed cost is much lower than steel. The cost of material and installation equipment can be minimized, and the installation cost depends heavily upon the integrity of the installation crew. A short drive, which will fail rapidly, can be used to attain the illusion of a good long-term foundation repair.
Drainage and Chemical Soil Stabilization Injection
Drainage correction is used to prevent further problems, sinking or heaving, but cannot lift a failed foundation. The same is true of chemical injection.
Mudjacking and Foam Injection
Mudjacking or foam injection of foundations provides a temporary lift, but does not get to the underlying cause of many failing foundations. With time, most mudjacked slabs will again sink. This is a low budget, relatively low performance system to install.
Drilled Concrete Piers or Poured Concrete Piers
For foundation repair, space limits installation equipment to hand held, gas powered augers. Typical depths achieved are in the range of 6 to 8 feet, although engineering requirements normally specify 12 feet. The system may fail and eventually sink. There is no validation that the bottom of the pier is resting upon high density soil. Material, labor and equipment cost are minimal. Poured concrete piers are optimal for new house construction.
Pad and Block
Pad and block piers are shallow support systems commonly used for wing walls. Due to shallow installation, they are subject to heave and drop as the soil moisture increases (soil expands) and decreases (soil shrinks). Used in the 80s and 90s for foundation repair, the system proved highly problematic.
Hybrid Concrete / Steel Piers
The system is, in our opinion, of questionable value. The steel leader is only of value if it enables penetration to rock. Most often the concrete cylinder pier system limits depth and the steel can only act as a drive facilitator, but not as part of the support system.
Summary
Granite Foundation Repair firmly believes that Steel Piers (straight or helical) are the pier of choice for foundation repair in the Dallas area. Pressed concrete piers are suitable, provided that the installation crew is dependable and not being paid a per pier installation incentive. Drainage correction is a peripheral activity that may be required to prevent recurring damage to other areas of the structure, or to prevent heaving.
We know that this is a lot of information. Give us a call at 972-412-2171 and we will be happy to address any of your questions. Or, you may complete our contact form.