A method name is not a diagnosis. Piers, grout, and foam can each be useful in the right setting. The choice should follow the building’s load path, movement pattern, soil conditions, water conditions, access, and repair objective.
Your situation
Tap a question that matches what you are trying to understand. The six method names stay visible below whether you tap or not.
See a name you don’t recognize — drilled shaft, caisson, CFA, H-pile, sheet pile, Geopier?Other Deep Foundations →
The methods
Helical Piers
Steel elements installed by rotation to provide a deep-foundation load path. Not an automatic answer to every crack or moisture-related movement.
Micropiles
Small-diameter drilled-and-grouted reinforced foundation elements. Used for structural support and, in some work, in-place earth reinforcement. Not simply “stronger piers.”
Push Piers
Steel resistance piers pressed using an existing structure as installation reaction. Not torque-installed helical piers. Not automatically suitable for a light structure or an unresolved water problem.
Compaction Grouting
Stiff, low-mobility grout used to displace and densify suitable ground. Not foam. Not a conventional deep pile.
Foam Jacking
Expanding polyurethane used to fill voids, restore contact, and lift concrete in controlled stages. Not a pile. In suitable documented conditions it can be used for more than cosmetic slab lifting, and it can be a reasonable alternative to a pier proposal when the problem is treatable soil or voiding and a separate deep load path is not required.
Other Deep Foundations
A vocabulary guide to systems commonly encountered in commercial, industrial, infrastructure, marine, retaining, and new-construction work. Not a sixth residential repair product.
Start here
- Is the goal deep load transfer, soil improvement, void filling, slab lifting, or retaining soil?
- Is the movement active, historic, seasonal, localized, or widespread?
- Have drainage, irrigation, plumbing, erosion, and soil-moisture change been considered?
- What information supports the proposed method?
A method is only as good as the job it is asked to do. Sometimes the quieter option is the better one. Soil, water, access, structure weight, scope, and cost can make a simpler method the honest answer.
Core questions
What problem is the method meant to solve?
A proposal should identify whether the intended job is:
- Transfer structural load deeper.
- Improve shallow or intermediate-depth soil.
- Fill voids and restore contact beneath a slab.
- Lift a slab or foundation toward a target elevation.
- Retain soil, control erosion, or support an excavation.
- Support new construction or an addition.
A method can be technically sound and still be wrong for the stated problem.
Which repair methods are actually comparable?
- Helical piers, push piers, and micropiles may be compared when the question is how to create a structural underpinning load path.
- Compaction grouting, rammed aggregate piers, and certain resin-injection approaches may be compared when the question is whether ground improvement can create adequate support.
- Foam jacking and cementitious slabjacking may be compared when the question is void filling, slab support, or controlled slab elevation.
- A project can require more than one category: underpinning for a footing and void filling beneath an adjacent slab, for example.
Is the goal stabilization or lift?
Stabilizing movement and lifting a structure are related but different objectives. Lift can close gaps or restore elevations. It can also stress finishes, plumbing, brittle masonry, utilities, and parts of the structure that are not moving uniformly.
A proposal should state whether lift is necessary, what degree of lift is intended, what could limit it, and what will be monitored during the work.
Is water part of the mechanism?
Water is not automatically the cause of movement. It should not be treated as an afterthought. Roof runoff, surface drainage, irrigation, plumbing leaks, erosion, perched water, groundwater, and moisture-sensitive soil can change support conditions.
A deep foundation system may still be appropriate when water is involved. The proposal should explain whether the water mechanism has been addressed, controlled, or intentionally separated from the structural-repair scope.
Where to read next
These are orientation cards. They do not diagnose a house.
Was I told the footing needs deeper support?
Was I told the slab has a void or has settled?
Was I told the soil itself needs improvement?
Did the proposal use a name I do not recognize?
Was the problem identified after rain, irrigation, a leak, or erosion?
Start with water and soil behavior before selecting a repair system.
More questions
No. “Bedrock” is not a complete design explanation. Ask what material was encountered, at what depth, whether it is competent for the intended load, how the system engages it, and how the existing building connects to the proposed support.
No. A deeper system may be appropriate where shallow support is inadequate. Depth alone does not solve a moisture problem, a drainage problem, a structural-connection problem, a void, or an incorrect diagnosis.
Sometimes their scopes overlap around voids, loose ground, slab support, or controlled lifting. Their materials and intended mechanisms are different. Compaction grouting uses stiff low-mobility grout to displace and densify suitable ground. Polyurethane injection uses expanding resin that can fill voids, create confinement, and potentially lift or improve support.
The reason may be legitimate: access, equipment size, building weight, footing condition, vibration limits, depth of weak soil, obstructions, soil type, water conditions, desired lift, or cost.
The owner should still ask what alternatives were considered and why they were ruled out.
Yes. A project may combine drainage correction, underpinning, void filling, soil improvement, monitoring, or slab repair. A combination is not automatically more complete. It should be tied to distinct identified problems.
Ask how load moves from the existing footing, wall, column, or slab into the proposed repair and then into the ground.
A high-capacity pier does not automatically make a weak, narrow, cracked, poorly reinforced, or eccentric footing suitable for concentrated bracket loads.
Questions to ask before choosing a method
- What movement or support problem is this method intended to solve?
- What investigation supports that explanation?
- Is the goal stabilization, lifting, deep load transfer, soil improvement, void filling, retaining soil, or support for a new load?
- What is the load path from the building into the proposed system?
- What is outside the scope — drainage, leak repair, slab work, utilities, monitoring, engineering?
- How will success be defined: stabilization, achieved lift, restored slab support, reduced settlement risk, or cosmetic repair?
The right repair is not the loudest tool, the deepest tool, or the cheapest tool. It is the method that matches a demonstrated problem and a clearly explained objective.