Settlement & Piers in St. Paul
Push piers and helical piers driven to stable soil to stop sinking corners.
A sinking foundation and a settling foundation are the same problem at different speeds: part of the foundation has dropped. A little even settling in the first years after a house is built is normal. The problem is differential settlement: one corner or side sinks while the rest stays put. That twists the structure, and it shows up as cracks and sticking doors.
Signs of settlement
- Stair-step cracks in block or brick, often near a corner
- Diagonal cracks running from the corners of windows and doors, inside or out
- Floors that slope toward one side of the house
- Doors and windows that stick or won't latch, especially if they used to work
- A crack where one side has dropped lower than the other
Cracks that appear suddenly, keep growing, or show up together with sticking doors mean the movement is active. Mark and date them (see the crack guide) and get an inspection.
Why foundations settle
- Loose fill. Soil trucked in and spread during construction is much looser than undisturbed ground. If it wasn't compacted well, it keeps compressing under the house for years. This is a common story in subdivisions built on graded or filled lots.
- Soft or organic soil. Former wetlands can leave peat and muck behind. MnDOT's geotechnical guidance describes organic soils as having a high potential for settlement.
- Soil that dries out and shrinks. Clay shrinks as it dries. Large trees near the house pull a lot of water from the soil in summer.
- Soil that gets too wet. Leaking pipes, bad downspouts, and poor grading soften the soil under footings.
Rule out drainage first. If water is soaking the soil under one corner, fixing the water may be cheaper than piers, and piers won't solve the water problem anyway.
Push piers vs. helical piers
Both are steel posts installed under your footing to reach firmer soil or rock. The difference is how they get there.
| Push piers | Helical piers | |
|---|---|---|
| How they're installed | Driven straight down with a hydraulic ram, using the weight of the house to push against | Screwed into the ground with a hydraulic motor, like a giant screw |
| Best for | Heavier homes with enough weight to drive the pier deep | Lighter structures: one-story homes, porches, additions, decks, and slabs |
| How capacity is checked | Each pier is load-tested as it's installed | Installation torque is used to estimate each pier's capacity |
| Cost | Usually less steel for the same depth | Often a bit more per pier |
For a light home, the house can start lifting before a push pier reaches good soil. That's why lighter structures usually get helical piers. The right choice depends on the weight of the house and the soil, which is why an engineer's input helps.
Can piers lift the house back to level?
Sometimes, partly. After piers are set, the house can be raised gently and evenly, and some homes come back close to their original level. Manufacturers describe the goal as getting as close to the original position as the structure will allow. Cracks may close up, but old framing, drywall, and brick don't always cooperate. Treat stopping the sinking as the guaranteed part and lifting as the bonus.
Sinking slabs: garage floors, walks and patios
Settled slabs are usually lifted by pumping material underneath:
- Mudjacking pumps a heavy cement-and-soil slurry under the slab. It's cheaper, but the slurry adds weight to soil that already failed and can wash out over time.
- Polyurethane foam is injected through small holes, cures quickly, and weighs very little. It usually costs more.
Slabs that need real support, not just a lift, can get their own steel slab piers.
When to bring in an engineer
Underpinning is structural work. Engineering guidance recommends a structural engineer design the repair, often with a geotechnical engineer taking at least one soil boring to find out how deep good soil is. If a contractor proposes piers, ask whether an engineer has looked at it, and what depth they expect.
Permits
St. Paul requires a building permit for structural revisions to a home, and underpinning falls into that category. Confirm with the Department of Safety and Inspections (651-266-8989). Homes in historic preservation areas need permits even for exterior repairs. Suburbs run their own permit offices. See your city page.
What it costs
Piers usually run $1,000–$3,000 each (national 2026 cost data), with helical piers toward the top. A typical settled corner or wall takes somewhere around 6 to 10 piers, so most jobs land in the five figures. Engineering and soil borings add to that. See the cost guide.
Questions homeowners ask
My house is 50 years old. Why would it start settling now?
Something changed under it: a plumbing leak, a new drainage pattern, a big tree's roots, or a very dry or very wet stretch of years. Finding that trigger is part of the fix.
My house was built on fill. Should I worry?
Not automatically. Well-compacted fill performs fine. Watch for the signs above, especially in the first 10–15 years.
A contractor says I need piers. How do I know?
Ask what is causing the settlement, how many piers and how deep, and whether an engineer has reviewed it. A second opinion is reasonable on a five-figure job.
Push piers or helical piers for a one-story house?
Lighter homes often get helical piers, because a push pier needs the building's weight to drive it deep enough. An engineer can confirm for your house.
Sources
- Earth Contact Products, Steel Piers Technical Service Manual, Chapter 5 (resistance piers, slab piers, lifting).
- Patrick Nevison, P.E., “Foundation repair using push piers and helical piers,” WATERPROOF! Magazine, December 2024.
- Hubbell / CHANCE, history of the torque-to-capacity correlation for helical piles.
- ICC-ES AC358, acceptance criteria for helical pile systems.
- MnDOT Geotechnical Manual, Appendix A, Geology of Minnesota (organic soils).
- University of Minnesota Extension, soil orders of Minnesota.
- This Old House, “Foundation settling vs. foundation problems.”
- City of Saint Paul DSI, “When is a Permit Required?”
- Cost data: Fixr, This Old House and HomeAdvisor (2026).
Areas we serve
St. Paul, Woodbury, Maplewood, Oakdale, Cottage Grove, Stillwater, West St. Paul, North St. Paul, Lake Elmo