Foundation Lifting & Underpinning

Both helical and push piers do the same job — transfer load from a failing footing to competent bearing strata below — but the way they get installed and how the bearing signal is read is different. The right one depends on the soil profile, the load, and the site access.

Helical piers:

• Steel shaft with welded helical plates driven into the soil with a hydraulic torque motor, rotating the pier into position like a screw.
• Installation torque correlates to soil bearing capacity — reaching a specified torque value at design depth is the installer's confirmation that the pier has found competent strata.
• Work particularly well on lighter residential loads, tight-access sites (the torque motor is compact), and soils that take the helix cleanly.
• Load-tested via torque correlation; supplemental static load test available where the engineer specifies one.
• Common shaft sizes for residential range from 1.5-inch square through 3.5-inch round depending on load.

Push (resistance) piers:

• Sections of steel pipe hydraulically pushed into the ground using the structure above as the reaction load — the weight of the house itself is what drives the pier down.
• Refusal pressure at design depth is the bearing signal — the pier stops driving when hydraulic pressure at the ram reaches a value that confirms competent strata.
• Work well on heavier residential and light commercial loads, and on soils where the helix profile doesn't grip cleanly.
• Very reliable bearing confirmation because the installed load is the same load the pier will carry in service — no correlation is required.

On most residential jobs the on-site walk plus a soil profile read (available from the county soils map, from a geotech report if one exists, or from what turns up during the first pier install) gives a clear read on which one fits. If the situation is on the line, we'll spec whichever the load path and profile more strongly favor and explain the trade.

Once piers are installed, hydraulic rams at the bracket lift the structure in controlled increments while the lift is watched at multiple points around the foundation. How much of the original elevation comes back depends on how the structure moved and what the finishes above can tolerate.

• Full recovery to original elevation is possible when the structure is intact, the failure mode is uniform loss of bearing under the lifted section, and finishes above can move without cracking further. This is more common on newer construction and on homes that haven't been through many years of accommodation.
• Partial recovery (arresting further movement and recovering some of the elevation) is the norm on older homes where brick veneer, plaster, and finishes have adapted to the settled position over years. Pushing for full recovery in that situation can crack finishes worse than the settlement did.
• Stabilization-only lifts are appropriate when the structure has moved enough that recovery would tear the house apart above — the pier install locks the foundation in place, stops further settlement, and interior finishes are then repaired at their current elevation.
• The written scope specifies the lift target for each point before the rams go in, and the recovered elevation at each lift point is measured and documented after the lift.
• Interior finish work, door and window re-adjustment, and cosmetic crack repair after the lift is typically the homeowner's call — some prefer to live with the settled interior detail; others want re-plaster and re-trim scheduled as a follow-up.

We walk the achievable lift target with you on the on-site evaluation so the number in the scope matches what the house can actually take.

A large share of residential foundation movement in North Carolina traces back to soil moisture cycling and site drainage — and piering a corner that keeps getting soaked will just settle again unless the water source is addressed.

• Piedmont red clay swells when saturated and shrinks when dried. The vertical movement across a full seasonal wet-dry cycle can be measurable at the footing — enough, over years, to lift and drop a corner an inch or more.
• Trees within twenty feet of the foundation dry the clay through root suction, especially in late summer, and can pull a footing down toward the tree over time.
• Gutters discharging at the wall or downspouts dumping within a foot of the foundation feed water directly into the expansion zone under the footing.
• Grade sloping toward the house instead of away from it turns every rain into a soil-moisture event at the footing.
• Fill soil placed under an addition or an unpermitted extension often wasn't compacted properly, and settlement shows up in the first two to three years — piers are the right long-term answer when the fill is deep and the load is heavy.
• Plumbing leaks under the slab wash the base out; the fix is the plumbing repair first, then piering or lifting as needed.
• Missing or clogged foundation drains around a basement wall build hydrostatic pressure that pushes walls in — that's a wall anchor situation, not a pier situation.

Any real underpinning job addresses the drainage cause alongside the structural fix. The walk-through report calls out the drainage issues we see and specifies whether the pier install alone will hold, or whether a drainage correction needs to happen either before or alongside the lift.