What are the reasons and purposes of underpinning service?

Underpinning means going under an existing foundation and carrying the load down to firmer ground, so a footing that has lost its soil stops dropping. The purpose is structural: stop active settlement, support a sagging foundation, and put the weight back on solid bearing instead of loose backfill. In our world that is done with helical piers, which start at $2,700 per pier for the first three, then $2,200 per pier after that and carry a 25-year engineered warranty. We do not pour or replace whole foundations. We repair them.

What underpinning does

Your foundation sits on a footing, and that footing sits on soil. When the soil under one part gives way, that corner or wall drops and the house cracks along with it. We screw helical piers down past the bad dirt until they hit firm bearing, and the piers take over the load. The footing stops resting on soil that can move and starts resting on steel that does not. That is the whole point. We self-perform the structural lifting and helical installs in-house, so the crew on your job is our crew.

Why a footing loses its soil in New Hampshire

The dirt right against your foundation is disturbed backfill, the loose fill the builder pushed back in after the foundation went up. It drains slow and holds water. When that fill stays wet and then freezes, NH frost heave pushes, lifts, and settles unevenly. Over years the footing on the worst side sinks, which is why settlement usually shows up at one corner, not across the whole house.

The reasons people call us for it

Here is what tells us a footing is still moving and underpinning is on the table:

• A crack that keeps widening, wider at the top than the bottom.
• A diagonal crack running off the corner of a window or door.
• Floors that slope. Set a marble down and watch it roll to one side.
• Doors and windows that used to close fine and now stick.
• A whole corner or wall section dropping over time.

If you have one thin vertical crack that stays the same size, you probably do not need underpinning yet. That is usually settling, and settling stops on its own. Mark it with a pencil line and a date. If it grows, call us.

When a lighter fix does the job instead

Underpinning is for the footing, and it is not always the answer. We will tell you that to your face. If a wall is bowing but the footing is fine, we stabilize the wall: carbon-fiber straps start at $850 each for a wall that has moved a little, warrantied 25 years, and a power brace at $1,300 per brace handles a wall that needs more muscle. If a crack only leaks and the wall is stable, that is a waterproofing job, not a structural one. We inject it with epoxy or polyurethane, sealed for good, and crack injection starts at $1,000 to $3,000 with a 10-year warranty. If a beam sags or a floor bounces, a lally column or floor support at $1,300 to $2,500 takes the load, warrantied 10 years. We save underpinning for when the footing itself is the problem.

What it costs and what we price after we look

Helical piers start at $2,700 per pier for the first three, then $2,200 per pier after that, engineered and warrantied 25 years. The real number depends on how many piers your footing needs and how deep they go to reach firm ground, which is what the free inspection is for. Some jobs we price only after we see them: a full foundation-wall rebuild, wall anchors, and steel I-beams. If you are asking about a brand-new foundation or new construction, that is not us. We repair foundations, we do not build new ones.

One thing we steer people away from is digging out the outside of the foundation to “waterproof” it. In our field experience that fix fails in about two to three years as the soil settles again. If water is the real problem, the durable fix is interior drainage. See /basement-waterproofing/.

For the full menu of structural fixes, see /structural-and-foundation-repair/ and /foundation-repair/. Deep-set work lives on /helical-piers/ and /supplemental-support/. Rotted sills under the framing go to /sill-replacement/. Every structural fix we do is backed by /the-603-guarantee/.

A note on coverage: your homeowners policy almost never pays for gradual settlement, since insurers treat it as wear and maintenance rather than a sudden event. Check your own policy. The Insurance Information Institute explains what standard policies do and do not cover. For the building-science side of foundation soil and frost, the DOE Building America program is a neutral reference (basc.pnnl.gov).

Book a free look

Get a real answer on whether your footing actually needs underpinning. We give you a free inspection and a free estimate, with a quote within 24 hours. Call 603 Basement Solutions at 603-610-1770 or book your free inspection. Trusted by 5,000+ homeowners in New England, 4.9 stars across 250 Google reviews, BBB A+ accredited and fully insured.

Related questions

Is underpinning the same as helical piers? Underpinning is the goal: carry an existing footing down to firm ground. Helical piers are how we do it. We screw the piers past the loose backfill to solid bearing, then they hold the load. Helical piers start at $2,700 per pier for the first three, then $2,200 per pier after that with a 25-year engineered warranty.

Do I always need underpinning if my foundation has cracks? No. Most cracks are not a footing problem. A thin crack that stays put is usually settling and only needs sealing if it leaks, from $1,000 to $3,000. A bowing wall gets carbon-fiber straps from $850 each or a power brace from $1,300 per brace. Underpinning is for when the footing itself is dropping.

Can you underpin a brand-new foundation or new build? That is not us. We repair existing foundations, we do not pour new ones. If an existing footing is failing, that is where helical piers come in.

How fast can you tell me if I need it? We come look for free, then send a written estimate with a quote inside 24 hours.