Home Improvement: How do you deal with cracks in a house wall?

You deal with a crack in a foundation or basement wall by matching the fix to the cause. A narrow non-moving crack gets sealed with epoxy or polyurethane injection, starting around $1,000 to $3,000. A wall that is bowing or shifting needs structural reinforcement, like carbon-fiber straps from $850 each or a power brace from $1,300 per brace. The first step is always a free inspection so you fix the right thing.

Not every crack means the same thing. Some are cosmetic. Some are a warning. Here is how we sort them in the field across New Hampshire, Maine, and Massachusetts.

Hairline cracks in drywall or plaster

Thin cracks in interior drywall, especially above a door or window, are usually settling or seasonal movement. New homes settle. Old homes breathe with the weather. These are cosmetic, and you patch them with joint compound and paint. You don’t need us for that yet. If a drywall crack keeps coming back in the same spot after you patch it twice, that can mean the structure under it is still moving, and that is worth a look.

Cracks in a poured concrete foundation wall

A thin vertical crack in a poured concrete wall is common and often just shrinkage from when the concrete cured. If it is dry, we seal it with crack injection so it stays dry and stops growing. Crack injection runs from $1,000 to $3,000 and carries a 10-year warranty.

A crack that leaks water is a different job. Water gets in because the soil against your foundation is disturbed backfill, the loose dirt that got put back when the house was built. That fill drains slowly and holds water against the wall. Injection seals the crack itself. If water is coming in at the floor wall joint too, that is a drainage problem, and the durable answer there is interior drainage, not patching from outside. We do not do exterior excavation waterproofing. In our experience that fix tends to fail in a couple of years, and you are back to a wet basement. Interior drainage lasts.

Horizontal cracks and bowing walls

This is the one to take seriously. A horizontal crack running along a block or concrete wall, or a wall that bows inward, usually means soil pressure is pushing on it. In New Hampshire, frost heave is the main culprit. Wet soil freezes, expands, and shoves the wall in.

A bowing wall does not heal. It needs to be stabilized. For most walls we install carbon-fiber straps, from $850 each, which lock the wall and stop further movement. They carry a 25-year warranty. For a wall under heavier load we use a power brace, from $1,300 per brace, warranted 10 years. If the foundation has dropped or settled, that is a footing problem, and we may recommend helical or push piers to lift and hold it. Helical piers carry a 25-year engineered warranty.

We self-perform our structural lifting and helical work in-house. No subcontractors guessing on your foundation.

Stair-step cracks in a block or brick wall

Cracks that climb diagonally through the mortar joints, like a staircase, point to settling at one corner of the house. Sometimes it is minor. Sometimes it means the footing under that corner is sinking. We measure it, watch it, and tell you plainly whether it needs piers or just monitoring. If it does not need work yet, we will say so.

What drives the cost

Three things set the price: how the crack is moving, how long the affected section is, and what is causing it. A single dry injection is the low end. A bowing wall that needs several carbon-fiber straps is more. A settled footing that needs piers is more again. Some jobs we cannot price until we see them, like a full foundation-wall rebuild, wall anchors, or steel I-beams. We price that after we see it. 603 repairs foundations, we do not pour new ones, so if you are asking about a brand-new foundation, we will point you to the repair we can do.

Financing is available through Hearth, subject to approval. We make nothing on it.

A quick way to tell normal from serious

Hairline and vertical, dry, not growing: usually cosmetic or shrinkage. Horizontal, stair-step, wide, leaking, or getting longer: get it inspected. The U.S. Department of Energy’s Building America program notes that foundation moisture and soil movement are leading causes of structural and comfort problems in homes (basc.pnnl.gov). When you are unsure, measure the crack with a pencil mark and a date. If it spreads, call us.

A wall crack is not something you want to guess at alone. We give you a free inspection and a free estimate, with a quote within 24 hours.

Learn more about how we fix walls and foundations:

• Structural and foundation repair
• Foundation repair
• Helical piers
• Supplemental support
• Sill replacement
• Basement waterproofing
• The 603 guarantee

Call us at 603-610-1770 or book your free inspection. We will tell you what your wall actually needs, and what it doesn’t.

Related questions

Is a crack in my foundation wall serious? It depends on the direction. Vertical and dry is usually shrinkage. Horizontal or stair-step, or any crack that leaks or keeps growing, means soil pressure or settling and should be inspected. We do free inspections across NH, ME, and MA.

Can you just fill a foundation crack with caulk? No. Caulk sits on the surface and fails. We use epoxy or polyurethane injection that fills the full depth of the crack and bonds it, starting around $1,000 to $3,000 with a 10-year warranty.

Why does my basement wall crack leak only when it rains? Because the soil against your foundation is loose backfill that holds water. When it rains, water pools there and finds the crack. Sealing the crack helps, and if water also shows at the floor wall joint, interior drainage is the durable fix. See basement waterproofing.

How long does a wall repair last? Crack injection is warranted 10 years. Carbon-fiber wall stabilization and helical piers are warranted 25 years. Transfer is conditional and voids if another contractor touches the work.