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Is a foundation crack serious? How to tell, and the cost
A vertical hairline crack is usually just shrinkage; a horizontal crack or bowing wall means real damage. An engineer's visit runs $400 to $1,500.
Updated · By 
Ben Sikes
How do you know if a foundation crack is serious?
A foundation crack's direction and shape decide who evaluates it: shrinkage cracking is usually minor, but a horizontal crack or bowing wall means the foundation itself may be bent or broken. A structural engineer's on-site visit and written opinion, the professional who prices this finding, runs $400 to $1,500 per visit (Today's Homeowner).
International Association of Certified Home Inspectors (InterNACHI)'s inspector training calls shrinkage cracking "rarely serious" and says a horizontal crack "indicates that the vertical supporting member" is "bent or broken" (InterNACHI, "Inspecting Foundation Walls and Piers,"); the table below has each pattern in its words. Your home inspector can tell you a crack exists and describe it, but the American Society of Home Inspectors' own Standard of Practice states inspectors are not required to "offer an opinion about the adequacy of structural systems and components" or "provide engineering or architectural services or analysis" (ASHI Standard of Practice). That is the inspector's job description, not a loophole: it is why the report names the crack and stops there.
One crack type has a documented pattern. InterNACHI states that "vertical cracks in foundation walls are relatively common, and typically result from shrinkage" (InterNACHI, "Avoiding Litigation: Foundations,"). The same source adds a caution worth keeping: "the truth is that all cracks are structural but not all of them are structurally alarming." That is true of a hairline vertical crack, and it is true of a wide horizontal one.
InterNACHI's own inspector-training manual draws the line between the low-risk pattern and the ones that need an engineer, in its own words:
| What you see | What InterNACHI says | Who evaluates |
|---|---|---|
| Vertical, hairline crack in the middle third of a concrete block wall | "Shrinkage cracking is rarely serious," though it is "often mistaken for settlement cracks" | Your inspector notes it; get an engineer to confirm it isn't the settlement pattern below |
| Diagonal crack stepping along the mortar joints, wider at one end than the other | Settlement cracks "taper, starting large at one end and then diminishing to a hairline crack at the other," and cracks "whose edges do not line up... indicate differential settlement due to inadequate foundations" | Structural engineer |
| Horizontal crack across a brick or block foundation wall | "Potentially serious, as it indicates that the vertical supporting member -- the foundation wall -- that is carrying a portion of the structure above is bent or broken" | Structural engineer |
| Wall section that looks pushed in or out of line | Settlement can cause "the subsequent buckling or displacement of the foundation wall above" | Structural engineer |
(InterNACHI, "Inspecting Foundation Walls and Piers,")
No primary or association source fetched for this page puts a number or a "safe" label on any of these by sight. If your report names one, this table tells you which pattern InterNACHI calls rarely serious and which it calls potentially serious, but only a structural engineer's evaluation, covered below, turns that into a decision.
How much does foundation crack repair cost?
Cost depends on what the crack turns out to be, which is why the answer is a table of repair methods, not one number. Kept marks foundation structural movement as a finding that needs a professional quote, not a formula price: if your engineer confirms movement, your memo marks that line for a professional quote rather than guessing at a number. Kept's methodology covers how the rest of a report's findings do get a formula price.
| Repair | Cost | Scope | Source |
|---|---|---|---|
| Structural engineer evaluation | $400 to $1,500 per visit | On-site inspection and a written opinion on cause and severity; rises with damage severity | Today's Homeowner |
| Epoxy or polyurethane injection | $200 to $1,000 | Fixr's crack-sealing price; the source does not state whether this covers one crack or a full job | Fixr |
| Carbon fiber straps | $4,000 to $12,000 | Wall stabilization for a bowing foundation; cheaper than steel bracing | Bob Vila |
| Steel bracing | $4,000 to $12,000 | Wall stabilization for a bowing foundation; pricier than carbon fiber | Bob Vila |
| Piering or underpinning | $10,000 to $40,000 | For a sinking or unstable foundation; includes excavation and temporary house jacking | Fixr |
These sources disagree because they price different jobs, not because one is wrong: a single injected crack and a foundation that needs piers are not the same repair. Get quotes against the scope your engineer writes, not against this table alone.
How much does horizontal foundation crack repair cost?
InterNACHI itself treats a horizontal crack as a wall-movement problem, not a shrinkage one: it calls sweeping or horizontal cracking of a brick or block foundation wall "potentially serious, as it indicates that the vertical supporting member... is bent or broken" (InterNACHI, "Inspecting Foundation Walls and Piers,"). Once a structural engineer confirms what is moving, the fix is one of the same wall-movement methods, not injection.
| Repair | Cost | Source |
|---|---|---|
| Carbon fiber straps | $4,000 to $12,000 | Bob Vila |
| Steel bracing | $4,000 to $12,000 | Bob Vila |
| Piering or underpinning | $10,000 to $40,000 | Fixr |
Which row applies depends on the engineer's finding, not the crack's length or width. Do not price a horizontal crack off injection costs: injection is scoped to a dry, stable crack, not to the pressure that bent the wall in the first place.
How much does concrete foundation crack repair cost?
A narrow, vertical crack in a poured concrete foundation wall is treated with injection: $200 to $1,000, epoxy for a stable crack and polyurethane for one that is actively leaking (Fixr).
| Repair | Cost | Source |
|---|---|---|
| Epoxy or polyurethane injection | $200 to $1,000 | Fixr |
| Structural engineer evaluation | $400 to $1,500 per visit | Today's Homeowner |
That injection price covers the crack itself, not an opinion on why it is there. If your engineer finds the concrete wall is bowing or shifting rather than just cracked, the repair escalates to carbon fiber straps, steel bracing, or piering, priced in the table above. Ask which category your crack is in before you price it.
Who evaluates a foundation crack, and how fast can you get a number?
A structural engineer is the professional who evaluates a foundation crack, at $400 to $1,500 per visit for the inspection and a written opinion (Today's Homeowner). That written opinion is what turns a crack the report can only describe into a scope a repair company can bid against. Every other way to get a dollar figure before your window closes is covered in how to get repair estimates during the inspection period.
What do you ask the seller for a foundation crack?
Ask for the engineer's evaluation first, priced and scoped, not a repair credit for a number nobody has yet. A request line for this finding looks like: "Foundation crack, east basement wall: structural engineer evaluation, $400 to $1,500 (Today's Homeowner), plus the repair the engineer's report specifies, priced from the table above once scoped." That gives the seller's side something to act on, unlike "fix the foundation," because it names the professional, the visit, and where the number comes from. What to ask for after a home inspection covers how big an ask like this is next to the rest of your list, and the repair request letter template has the wording to send it.
If your engineer confirms active structural movement, that finding can be a reason to walk away rather than negotiate: see when to walk away after a home inspection for how a large, hard-to-price finding differs from a merely expensive one.
Sources
- ASHI Standard of Practice (as of 2026-09-19)
- InterNACHI, "Avoiding Litigation: Foundations" (as of 2026-09-19)
- InterNACHI, "Inspecting Foundation Walls and Piers" (as of 2026-09-19)
- Fixr, "How Much Does It Cost to Repair a Foundation in 2026?" (as of 2026-09-19)
- Bob Vila, "How Much Does Foundation Repair Cost?" (as of 2026-09-19)
- Today's Homeowner, "How Much Does a Structural Engineer Cost?" (as of 2026-09-19)
Cost figures are modeled from public wage and materials data unless a line says observed. Kept is accountable for the numbers on this page, and corrections go to support@usekept.com. How we price.