Calling up foundation repair companies and asking how much it would cost is like lurching your smoking car into the mechanic’s parking lot and asking him how may dollars it will take to fix it without even popping the hood.
Both are going to say “it depends on what’s wrong.”
A major factor in foundation repair cost will generally depend on how many piers will be needed, of what type, and how deep they will need to go to reach bedrock or supportive stable soil.
My neighborhood sits on expansive clay soil that seems to be about ten to twelve feet above a layer of bedrock. There is plenty of room between the houses. The repair method of choice is underpinning with concrete pilings drilled or shoved down to the “point of refusal” and stacked on one another to create the pier.
Different foundation repair companies use slightly different techniques to keep the stacks stable, and there are variations in methods of attaching the foundation to the piers and spreading the load.
The guy next door needed 27 piers, while Dennis down the street only needed 13. The difference in the cost of foundation repair in these cases was about $1500.
Steel piers often come into play where the trip to bedrock or stable soil is longer and/or access to the foundation is limited by lack of space.
For example, if your problem foundation sits on unstable fill dirt in a zero-lot line neighborhood where there is barely enough room between the houses for a lawn mower you may be hearing about steel piers. They can be drilled at least 50 feet down and I’ve seen one foundation repair website claim they can go 70 feet down if that’s what it takes.
They are usually attached to the foundation with steel brackets and can be installed where space is tight. If the middle of the house needs underpinning, sometimes steel piers can be drilled down through the slab in the space within interior walls instead of having to pull up flooring or carpet.
Helical steel piers can have enlarged threading at the bottom called “anchor flanges” that twist into the soil and hold.They can also be configured to twist into softer bedrock such as the white chalk rock that runs through much of the Dallas area.
I was once on a remodeling job site in the Preston Hollow area of Dallas where a big new patio and pool house was being built across from the guest house. They sank a series of helical piers down to bedrock, twisted them into the soft rock like wood screw into 2x4s and then poured the slab over top, connecting to the piers. It would take an earthquake to move that slab and we don’t have many of those in these parts.
You can see where different situations call for different types of piers and that will certainly affect the cost. The prudent homeowner will have a professional licensed structural engineer inspect the foundation and recommend the best plan for foundation repair in writing with drawings and measurements, and then use a contractor that offers that method of repair and a transferable warranty.
Although less expensive, use your cousin and his van full of day laborers at your own risk.