Roof Truss Repair Cost and When to Replace (2026)
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💰 Cost Breakdown
| Item | Low | Average | High |
|---|---|---|---|
| Structural Engineer Assessment On-site inspection of damaged trusses with a written report specifying repair method, materials, and connection details. This report is required by building codes for any structural repair and guides the contractor's work. Some engineers include follow-up inspection in their fee. | $300 | $500 | $800 |
| Truss Sistering / Reinforcement (per truss) Bolting or nailing a new wood member alongside a cracked or split truss chord to restore structural capacity. The most common repair for minor to moderate damage. Uses dimensional lumber or engineered lumber (LVL) specified by the engineer. Includes hardware (bolts, split rings, gusset plates). | $500 | $1,000 | $1,500 |
| Gusset Plate Repair (per connection) Replacing failed metal gusset plates (the stamped metal connectors that join truss members at nodes). Gusset plates fail from corrosion, overloading, or pulling out of the wood. New plates are bolted through the truss members per the engineer's spec. | $200 | $400 | $700 |
| Full Truss Replacement (per truss) Removing a damaged truss and installing a new factory-built replacement. Requires temporary shoring of adjacent trusses and the roof load, crane access in some cases, and reconstruction of the roof surface above. The most expensive option, reserved for severe damage (rot, termite destruction, structural collapse). | $2,000 | $3,500 | $5,000 |
| Temporary Shoring (if needed) Temporary supports installed to hold the roof while damaged trusses are repaired or replaced. Uses adjustable steel posts or timber cribbing. Required whenever load-bearing capacity is compromised during the repair process. | $500 | $1,000 | $2,000 |
Structural Engineer Assessment
On-site inspection of damaged trusses with a written report specifying repair method, materials, and connection details. This report is required by building codes for any structural repair and guides the contractor's work. Some engineers include follow-up inspection in their fee.
Truss Sistering / Reinforcement (per truss)
Bolting or nailing a new wood member alongside a cracked or split truss chord to restore structural capacity. The most common repair for minor to moderate damage. Uses dimensional lumber or engineered lumber (LVL) specified by the engineer. Includes hardware (bolts, split rings, gusset plates).
Gusset Plate Repair (per connection)
Replacing failed metal gusset plates (the stamped metal connectors that join truss members at nodes). Gusset plates fail from corrosion, overloading, or pulling out of the wood. New plates are bolted through the truss members per the engineer's spec.
Full Truss Replacement (per truss)
Removing a damaged truss and installing a new factory-built replacement. Requires temporary shoring of adjacent trusses and the roof load, crane access in some cases, and reconstruction of the roof surface above. The most expensive option, reserved for severe damage (rot, termite destruction, structural collapse).
Temporary Shoring (if needed)
Temporary supports installed to hold the roof while damaged trusses are repaired or replaced. Uses adjustable steel posts or timber cribbing. Required whenever load-bearing capacity is compromised during the repair process.
📊 Factors That Impact Cost
Damage Severity
High ImpactA hairline crack in a bottom chord is a simple sister repair. A truss with multiple broken members, severe rot, or termite damage may need full replacement. The engineer's assessment determines which repair is appropriate.
Number of Affected Trusses
High ImpactProblems often affect multiple adjacent trusses. Water damage from a chronic leak may compromise 3–8 trusses. Per-truss costs decrease slightly with volume (crew is already on-site, shoring is shared), but total project cost increases.
Accessibility
Medium ImpactOpen attic trusses are accessible from inside. Repairs on cathedral ceilings, vaulted spaces, or low-clearance attics require working in confined spaces or removing finished ceiling material — adding 20–50% to labor costs.
Cause of Damage
Medium ImpactThe root cause must be fixed before or during the truss repair. Water damage requires fixing the leak source. Termite damage requires pest treatment. Overloading (e.g., from improper HVAC installation in the attic) requires rerouting the load. These fixes add to total cost.
Permit Requirements
Low ImpactStructural repairs require building permits in most jurisdictions ($100–$500). The permit process may require the engineer's stamped drawings. Inspection is required before closing up the repair with ceiling material.
💡 Money-Saving Tips
Get the engineer's assessment before calling contractors
Hiring a structural engineer first ($300–$800) provides an objective repair specification. Contractors then bid on defined work rather than writing their own scope — which prevents overbuilding and gives you comparable bids.
Repair rather than replace when the engineer approves sistering
If the engineer's assessment says sistering is structurally adequate, don't let a contractor upsell you to full replacement. A properly sistered truss performs identically to a new one at 30–50% of the cost.
Fix the root cause simultaneously to avoid repeat damage
If the truss damage was caused by a leak, spending $200–$500 to fix the leak during the truss repair prevents paying for another structural repair in 5–10 years.