Replacing termite-damaged floor joists typically costs $1,000-$6,000 for a limited repair and $6,000-$15,000 or more when many joists, flooring, or structural supports are involved. The cost to replace termite damaged floor joists depends on the number and span of joists, access below the floor, infestation treatment, and local labor rates.
| Item | Low | Average | High | Notes |
|---|---|---|---|---|
| One joist repair or replacement | $500 | $1,500 | $3,000 | Access and flooring removal affect price |
| Several joists in one room | $2,000 | $6,000 | $12,000 | Often includes temporary support and patching |
| Extensive structural repair | $8,000 | $15,000 | $30,000+ | May involve subfloor, beams, or crawl-space work |
| Termite treatment | $300 | $1,000 | $2,500+ | Separate from carpentry in many quotes |
Assumptions: U.S. pricing for standard dimensional lumber and ordinary access; regional labor, concealed damage, and finish restoration can change totals.
Typical prices for replacing damaged floor joists
A single accessible joist usually costs $500-$3,000 to replace, while a multi-joist repair commonly runs $2,000-$12,000. These ranges assume conventional wood framing, no major foundation repair, and damage limited to one room or a short floor span. A structural repair affecting multiple rooms can exceed $15,000.
Contractors may charge about $10-$30 per square foot of affected floor area for a combined structural repair, but this is not a reliable stand-alone rate: a small job still needs setup, shoring, and minimum labor. Replacing a joist is different from sistering a sound joist beside a weakened one; the latter may cost less but is appropriate only when an inspector or qualified contractor confirms the remaining wood is structurally sound.
What joist removal, lumber, and labor add to the quote
Labor and temporary support are usually the largest parts of the bill. A quote should identify whether it covers demolition, replacement lumber, termite treatment, and restoring the floor above the framing.
| Quote component | Typical price | Common scope | What changes it |
|---|---|---|---|
| Carpentry labor | $75-$150 per hour | Cutting out, fitting, fastening, and leveling | Crew size and confined access |
| Shoring and setup | $300-$1,500 | Temporary posts or supports during work | Floor load and span |
| Lumber and connectors | $100-$500 per joist | Dimensional lumber, engineered lumber, hangers | Joist size, grade, and length |
| Floor opening and patch | $300-$2,000 | Removing and replacing limited flooring | Finish type and access from above |
| Termite treatment | $300-$2,500+ | Localized treatment or broader control | Infestation extent and method |
Material itself may be a modest share, but matching older dimensions or using engineered lumber can add expense. For example, 16-32 hours at $75-$150 per hour implies $1,200-$4,800 in labor before materials and other charges.
How joist span, size, and access change repair cost
Longer spans, larger framing, and restricted crawl-space access can push a repair into a higher price tier. Replacing a short, standard 2-by-8 joist is generally simpler than handling a 20-foot span or a deeper 2-by-12 joist that supports a heavily loaded floor.
As a practical estimating distinction, damage limited to one or two joists across a 10-12-foot room may remain a localized project. If damage affects three or more joists, extends beyond a 200-square-foot area, or reaches a beam or sill plate, expect additional structural assessment and a larger scope. Low crawl-space clearance, plumbing or wiring in the way, and brittle flooring can add several hundred to several thousand dollars.
Where rot or insect damage is concealed, the initial quote may be conditional. Contractors commonly reserve a change order for additional damaged framing found after opening the floor; ask for the hourly rate and per-joist pricing for that work before signing.
Does termite treatment or an inspection belong in the budget?
Structural replacement does not stop an active infestation, so treatment and repairs should be scoped separately. A pest inspection may cost $75-$250, though some providers credit it toward treatment. Localized treatment can be around $300-$1,000; broader soil, bait, or whole-structure treatment often reaches $1,000-$2,500 or more, depending on the home and method.
For extensive damage, a structural engineer may charge roughly $300-$1,000 for an evaluation or letter. A permit may be required when work alters structural framing, particularly in jurisdictions with strict inspection rules; fees vary, often from about $50 to $500. Ask the local building department whether a permit and inspection are required, and confirm whether engineering is included in the contractor’s estimate.
When sistering joists costs less than full replacement
Sistering can reduce demolition and labor when the existing joist retains enough sound wood to support a properly attached reinforcement. A limited sistering repair may cost $300-$1,500 per joist, depending on length, access, and connectors. It is not a dependable shortcut when termites have hollowed the joist, damaged its bearing ends, or affected the supporting beam.
Ask the contractor to explain why replacement or sistering is suitable and how the repaired floor will be supported. A low quote that leaves compromised wood in place may not address the structural problem. Compare the repair scope, not just the total, and check whether flooring removal, disposal, treatment, and finish restoration are included.
Three realistic joist repair estimates by project scope
Project details make quotes easier to compare than a single per-joist number. These examples use ordinary access and midrange labor; difficult access or premium finishes can increase totals.
| Example | Work assumed | Estimated total |
|---|---|---|
| One accessible joist | 8-16 labor hours, one standard joist, limited floor opening, localized treatment | $1,200-$3,500 |
| Four joists in one room | 24-48 labor hours, temporary shoring, lumber and connectors, subfloor patch | $4,000-$10,000 |
| Six joists and nearby support damage | 48-80 labor hours, engineering review, larger floor opening, treatment and restoration | $10,000-$25,000+ |
These examples are not fixed bids. They exclude major foundation work and extensive finished-floor replacement unless noted in a contractor’s scope.
Lower the joist repair bill by controlling the scope
Get separate prices for structural carpentry, termite control, and floor restoration before authorizing extras. That breakdown reveals whether a quote includes work that another contractor lists separately and helps prevent duplicate treatment or demolition charges.
Keep sound flooring in place when the crew can reach the framing from below, and avoid replacing unaffected joists solely for convenience unless a structural professional recommends it. Obtain at least three written estimates based on the same joist count, dimensions, treatment plan, and finish scope. Before work begins, agree on the rate for concealed damage and require approval for any change order.