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Piers are deep supports for a settled foundation. They transfer house load from surface soil to deeper soil or rock. Three common pier types are push piers, helical piers and concrete piers. This post explains how each type works, where it fits and what to ask in a quote. It does not design a pier plan for your house. That plan needs an on site look and a floor level map.
Why piers are needed at all
Surface soil moves. Clay swells when wet and shrinks when dry. Fill soil compresses under load. Organic soil settles as it breaks down. A footing or slab that rests only on surface soil moves with that soil.
A pier bypasses surface soil. It reaches a layer that moves less. That layer may be dense sand, stiff clay at depth, shale or rock. Once a pier bears on that layer, it can support the foundation above it with less seasonal movement.
Pier depth is therefore a key design choice. A pier that stops inside active clay may still move. A pier that reaches stable material costs more in material and labor, but it gives a more durable support. Ask how depth was chosen for your lot.
Push piers: driven by house weight
A push pier, also called a steel push pier or resistance pier, uses steel sections driven into the ground by hydraulic pressure. The weight of the house provides resistance. The crew pushes one section after another until the pier meets a stable layer, shown by high driving resistance.
Push piers suit heavy loads. A house with a brick veneer, a two story load or a thick footing provides enough weight to drive a pier deep. Push piers can reach deep stable layers in many soils.
Push piers have limits. A light structure, such as a porch, a garage corner or a small addition, may not provide enough weight to drive a pier to depth. In that case, the pier may stop early or need a different method. Push piers also need access for a hydraulic drive unit at each pier point.
Installation is often fast once access is open. The crew excavates at the footing, attaches a bracket, drives pier sections and then lifts the foundation in small steps. The bracket transfers load from footing to pier. Ask what bracket type is used and how it is attached to your footing.
Helical piers: screwed into the ground
A helical pier uses a steel shaft with helical plates, like a large screw. A machine rotates the pier into the ground. Torque readings during installation help judge soil resistance. When torque reaches a target, the pier is judged to bear on adequate soil.
Helical piers suit lighter loads and tight access. They do not need house weight to drive them. They can be installed under a porch, a light addition or a structure where a push pier would lack resistance. They can also be installed in soils where driving is difficult.
Helical piers have limits too. Very hard rock can stop a helical plate. Very soft soil may need a larger plate or a deeper shaft to reach target torque. Shaft size, plate size and plate count affect load capacity. Ask for those details in a quote, so you can compare helical piers fairly.
Installation torque is a useful record. Ask for a log of final torque or depth for each helical pier. That log shows whether each pier reached its design target, or whether some piers stopped early.
Concrete piers: drilled and pressed options
Concrete piers form a deep concrete column in the ground. Two common forms are drilled piers and pressed concrete piers.
A drilled pier, also called a drilled shaft, is formed by drilling a hole, placing steel reinforcement and filling the hole with concrete. Drilled piers can carry high loads and can reach rock. They need drilling access, concrete curing time and a design for shaft diameter and reinforcement.
A pressed concrete pier uses precast concrete cylinders pressed into the ground, one segment at a time, using house weight or hydraulic pressure. Pressed piers can be installed with smaller equipment than a drilled shaft rig. They need enough load to press segments to a stable layer, similar to a push pier.
Concrete piers suit sites where a concrete column fits the soil and load better than a steel pier. They may be proposed where a deep shaft to rock is planned, or where a provider prefers concrete for a given soil profile. Ask for shaft diameter, reinforcement and concrete strength if a drilled pier is proposed.
How to compare pier types for your house
Start with load. A heavy brick house, a two story house and a slab with a thick edge beam each impose different loads at pier points. A provider should list load assumptions or explain why a pier type fits the load at each point.
Next, look at soil. Expansive clay with a deep active zone needs a pier that reaches below that zone. Sandy soil with a shallow stable layer may allow a shorter pier. Rock at shallow depth may favor a drilled pier that bears directly on rock.
Next, look at access. Interior piers need slab cutting. Exterior piers need excavation. A tight side yard, a driveway over a pier point or a finished basement can change which pier type is practical.
Finally, look at lift goal. Some jobs aim to stabilize only, with no lift. Some jobs aim to lift a settled area toward level. A pier type that stabilizes well may still need a careful lift plan to avoid cracking walls and tile. Ask for the lift goal in writing.
What a good pier quote contains
A good pier quote is more than a total price. It should contain a pier map. That map shows pier locations, pier type at each location, spacing and target depth. It should state a lift goal and areas that will not be lifted.
It should state bracket type for steel piers, shaft and plate details for helical piers, or shaft diameter and reinforcement for drilled piers. It should state what happens if a pier does not reach stable soil at the planned depth, and how price changes in that case.
It should state access work, excavation restoration and interior finish repair. It should state permits and inspections for your city. It should state a record format at the end, with pier depths, torque readings where relevant and lift amounts.
Read Foundation leveling and piering for the full leveling process. Read Slab foundation repair if your job is a slab job. Read Pier and beam foundation repair if your job is a raised floor job.
Common mistakes in pier quotes
A common mistake is comparing total price without comparing pier count and type. A quote with ten push piers is not the same job as a quote with twenty helical piers. Pier spacing, depth and type must match before price comparison makes sense.
Another mistake is assuming piers fix drainage. Piers support a foundation. They do not stop water from pooling near a slab or a wall. A pier job without drainage correction may still see soil movement around piers, especially in expansive clay.
Another mistake is lifting too fast or too far. A fast lift can crack walls, tile and plumbing. A lift to perfect level after years of settlement can cause more cosmetic damage than a partial lift. Ask the provider to explain lift limits and monitoring during the lift.
Questions to ask before you approve piers
Ask which pier type is proposed at each location and why. Ask for target depth and how depth was chosen. Ask for torque or resistance records where relevant. Ask for a lift goal and a monitoring plan during the lift.
Ask about plumbing testing after interior pier work. Ask about permits and inspections. Ask about finish repair included and excluded. Ask for references for pier jobs with similar soil, load and foundation type.
How our referral works
We do not choose a pier type for you. We connect you with a local provider for an on site look. That provider should give a written pier map, scope and price before work starts.
See the home page for cities in this batch and for service pages that explain each repair method.
Common questions
Which pier type is best for a house?
No single pier type is best for every house. The right type depends on load, soil, pier depth and access. Push piers suit heavy loads and deep stable layers. Helical piers suit lighter loads and tight access. Concrete piers suit drilled shaft work where concrete and steel form a deep column. A provider should match type to your lot, not to a sales preference.
How do I compare pier quotes fairly?
Compare pier type, pier count, spacing, target depth and lift goal, not only total price. A quote with fewer piers is not cheaper if it leaves a settled area unsupported. Ask for a pier map with locations and depths. Ask what happens if a pier does not reach stable soil at the planned depth, and how that change affects price.
Do piers stop all future foundation movement?
Piers reduce movement by transferring load to deeper, more stable soil. They do not stop surface soil from moving, and they do not fix drainage or plumbing problems. A pier job should be paired with drainage checks and moisture control where needed. Ask the provider what movement, if any, may still occur after piers are installed.
Are interior piers different from exterior piers?
Yes. Exterior piers go around the perimeter and avoid interior floor holes. Interior piers go through the slab to support a settled interior area. Interior piers need floor protection, slab cutting and finish repair. Exterior piers alone may not lift an interior low spot. Ask the provider why each pier location was chosen for your floor map.