When cracks appear on a concrete basement floor of an

Most cracks in a concrete basement floor are normal shrinkage, not a structural problem. A slab gets poured wet, then dries and pulls in on itself, so thin hairline cracks show up. Those are cosmetic. The ones worth a closer look are the wide cracks, the ones with one side higher than the other, and the ones that leak water. Those can point to settlement or pressure under the slab, and we look at them for free. Most floor crack repairs land around $1,000 to $3,000, and we give you the number after a free inspection.

Here is the plain version. A basement floor is a thin slab sitting on the dirt under your house. It is not holding the house up. The walls and footings do that. So a crack across the floor is usually the slab drying and shrinking, or settling into the fill below. That fill matters. When your house was built, the crew dug the hole, poured the foundation, then pushed the dirt back in. That backfill sits looser than the ground around it, drains slow, and holds water. Over time it settles, and a slab on it cracks as it follows the dirt down.

So what tells a normal crack apart from one we should treat?

A hairline you can barely fit a fingernail into is normal. Leave it alone. A crack wider than a quarter inch, or one where you feel a lip with your foot because one side dropped, is a settlement signal. A crack that weeps water after a hard New England rain is a different problem. Water coming up through a floor crack or seeping in along the floor wall joint means groundwater is pushing under the slab. That is a waterproofing fix.

What we look at during the inspection

We read the whole picture, not just the crack you called about. We check whether the floor is level, look at the walls for bowing or stair step cracks, because frost heave in NH pushes walls inward and wall movement can show up as floor cracks too, and we check the floor wall joint for water, moisture, and any musty smell. Then we tell you which bucket you are in.

If it is a quiet shrinkage crack, we will tell you to leave it. No work needed.

If the crack is leaking, the fix is usually our Forever Dry System, full perimeter interior drainage with a sump pump and a vapor barrier, so water under the slab gets collected and pumped out instead of finding a path up through your floor. We do not do exterior excavation waterproofing. In our field experience that route fails in a couple of years. Interior drainage is the durable fix.

If the floor is cracking because the slab or footing settled, that is structural and foundation repair. Depending on what we find, that can mean helical or push piers to reach stable ground under a settling section, carbon-fiber straps for a wall that moved, or lally columns and floor support if a beam over the slab needs to be carried better. We self-perform the structural lifting and helical installs with our own crew.

What drives the cost

A single crack injection sits at the low end, around $1,000 to $3,000. Carbon-fiber wall straps run around $850 each. Helical piers are bigger work because we reach down to load-bearing soil, so they run around $2,700 per pier for the first three, then $2,200 per pier after that. Lally column or floor support work is around $1,300 to $2,500. If your cracks turn out to be a water problem, basement waterproofing with the Forever Dry System runs around $3,000 to $30,000. Some jobs, like a full foundation wall rebuild, we price after we see it. We will not guess a number on those.

We give you a free inspection, a free estimate, and a written quote within 24 hours. Financing runs through Hearth, subject to approval, and we make nothing on it.

A quick word on warranties. Crack injection carries a 10-year warranty. Helical piers carry a 25-year engineered warranty. Carbon-fiber wall stabilization carries 25 years. The Forever Dry System carries a full transferable lifetime warranty, and it is 100% guaranteed to be dry for life! Transfers are conditional, so they hold as long as no other contractor or homeowner touches our work.

Trusted by 5,000+ homeowners across New England, rated 4.9 on Google over 250 reviews, BBB A+ accredited, licensed and insured. One note worth knowing: a floor crack from settlement or normal slab movement is usually not covered by homeowners insurance, since policies tend to exclude earth movement and gradual settling. Check your own policy. The Insurance Information Institute explains how those exclusions generally work.

Not sure which bucket your crack is in? That is what the free look is for. Call us at 603-610-1770 or book your free inspection and we will read it for you. See the 603 guarantee for the full terms.

Related questions

Is a leaking crack in my basement floor a structural problem? Usually no. A crack that leaks water is a groundwater issue, not the house settling. The fix is interior drainage and a sump, our Forever Dry System, which runs around $3,000 to $30,000.

How wide does a floor crack have to be before I worry? A hairline you can barely catch a fingernail in is normal shrinkage. Wider than about a quarter inch, or one side sitting higher than the other, is worth a free inspection.

Do cracks in the basement floor mean my foundation is failing? Not by themselves. The floor slab does not hold the house up, the walls and footings do. We check the walls and the floor level during the inspection to tell a cosmetic crack from a settlement crack.

What causes basement floor cracks in New Hampshire? Two common drivers here. The slab dries and shrinks after it is poured, and the loose backfill around the foundation settles and holds water. NH frost heave can also push walls inward and show up as floor cracking.