How to fix exposed foundation rebar

Exposed foundation rebar gets fixed by removing the loose, crumbling concrete around it, cleaning the rust off the steel, coating the bar to stop new rust, then rebuilding the patch with a bonding repair mortar. That is the standard fix for small spots. If a long run of rebar is showing, or the concrete is cracking along the bar, the wall needs a structural look before any patching. We give you a free inspection and a free estimate, with a quote within 24 hours.

Why rebar gets exposed

Concrete covers the steel for a reason. The cover keeps water and air off the bar. When the cover chips, spalls, or wears thin, the steel starts to rust.

Here is the part that surprises people. Rust takes up more room than the steel it came from. So as the bar rusts, it swells. That swelling pushes the concrete off from the inside. More concrete pops loose. More steel shows. The damage feeds itself.

What thins the cover in the first place? In New Hampshire it is usually water plus freeze. Water gets to the wall through disturbed backfill. That is the loose fill put back around your foundation when the house was built. It drains slow and holds water against the concrete. Then winter hits. Frost heave pushes on the wall. The concrete cracks, water gets in, the cycle runs.

The small-spot fix

A few inches of bar showing, with sound concrete around it, is a repairable patch.

The steps are simple. Chip out the loose concrete back to solid material. Wire-brush or grind the rust off the bar. Coat the steel with a rust-inhibiting primer so it stops corroding. Then pack the void with a polymer-modified or bonding repair mortar and feather it flush. Cure it. The patch should outlast the spot it replaced.

You can do a tiny cosmetic spot yourself. A clean garage corner with a half-inch of bar peeking out is a weekend job. We will tell you when it is that simple. You do not need us for that.

When it is not a patch

Some signs say stop and call.

Long runs of rebar showing along a beam or footing. Concrete cracking or bulging in line with the bar. A wall that is leaning, bowing, or stepping. Rebar that is rusted thin or gone in spots. Any of those means the steel may not be carrying its load anymore, and a skim of mortar will not bring it back.

That is foundation work, not a patch. Depending on what we find, the fix could be crack injection for a tight crack $1,000 to $3,000, carbon-fiber straps to stabilize a bowing wall $850 each, a power brace for more push resistance $1,300 per brace, or piers to stabilize a settling footing $2,700 per pier for the first three, then $2,200 per pier after that. Sister-wall or sill-and-beam work runs deeper. A full wall rebuild is its own job, and we price that after we see it.

We self-perform our structural lifting and our helical installs in-house, so the crew that scopes it is the crew that fixes it.

What drives the cost

A cosmetic patch is cheap. A structural repair is not, and the price depends on what the bar is telling us.

Crack injection on one tight crack $1,000 to $3,000 sits at the low end. Carbon-fiber straps $850 each depend on wall length. A power brace $1,300 per brace adds steel and labor. Helical piers $2,700 per pier for the first three, then $2,200 per pier after that depend on depth to load-bearing soil and how many you need. Lally column or floor support work $1,300 to $2,500, auxiliary sister wall about $1,350 per linear foot, and sill and beam replacement $7,000 to $40,000 each scope on their own. We do not guess these blind. We see it, then we price it.

If the rebar is exposed because water keeps hitting the wall, fixing the water matters too. Interior perimeter drainage is the durable fix for a wet basement. See our basement waterproofing page for how the Forever Dry System works.

For the structural side, start at our structural and foundation repair hub. You can also read up on helical piers, sill replacement, and supplemental support. Every repair is backed by the 603 guarantee.

For general guidance on foundation and water issues around a home, the DOE Building America program (basc.pnnl.gov) covers foundation moisture and drainage, and the Insurance Information Institute (iii.org) explains how foundation damage interacts with homeowners coverage.

Book your free inspection

Not sure if your exposed rebar is a patch or a repair? We will look at it and tell you what we find. Call us at 603-610-1770 or book your free inspection. Free inspection, free estimate, quote within 24 hours.

Related questions

Is exposed rebar dangerous? A small cosmetic spot is not urgent. But exposed rebar that is rusting along a long run, paired with cracking or a leaning wall, can mean the steel is losing strength. That one needs a look before it gets worse.

Can I just paint over exposed rebar? No. Paint traps the rust and the bar keeps swelling under it. You have to chip out the loose concrete, clean the steel, coat it with a rust inhibitor, then rebuild with repair mortar so the cover is restored.

Does exposed rebar mean my foundation is failing? Not by itself. Plenty of walls have a chipped spot or two from age and water. Failure shows up as bowing, leaning, stepping cracks, or rebar rusted through. If you see those, get it scoped. If you do not, a clean patch is usually enough.

Will homeowners insurance cover exposed rebar repair? Usually not, since most policies treat gradual wear, rust, and settling as maintenance rather than a covered loss. The Insurance Information Institute (iii.org) explains what foundation issues policies tend to cover. Check yours.