Roof Truss Repair: What to Do and What It Costs
A broken roof truss can usually be repaired, but only to a repair detail drawn for that truss by the truss maker, a truss designer or an engineer; the building code does not allow improvised fixes. HomeGuide puts a broken truss repair at $500 to $5,000. Fire and collapse damage often means new trusses, and cracks where the ceiling meets the walls can be truss uplift rather than damage. Pick what happened below for who to call and what it costs.
What happened to the truss?
Pick the closest match.
or the truss designer or an engineer, working from the truss drawings
plate makers publish standard details for simple breaks
HomeGuide, broken roof truss repair
take the load off it and send photos of the damage
HomeGuide: $30 to $80 an hour
no cutting, splicing or other alteration without a design professional
A guide to who to call, not a diagnosis. Only someone who has seen the truss and its drawings can say how to repair it.
Replacing trusses?
If the answer is new trusses, these two tools size them and price the roof that goes back on.
What the building code requires
A roof truss is an engineered product, and the 2024 International Residential Code treats it that way. Section R802.10 requires trusses to be designed to accepted engineering practice, metal-plate-connected trusses to the ANSI/TPI 1 standard, with design drawings approved by the building official. Section R802.10.4 then rules out improvising:
- Truss members must not be cut, notched, drilled, spliced or otherwise altered without the approval of a registered design professional.
- Loads beyond the design, such as an HVAC unit or a water heater, must not be added unless the truss is verified to carry them.
So the question is never only whether a truss can be fixed, but who designs the fix. Our roof trusses guide explains the parts named below: chords, webs and the metal plates at each joint.
What to do when you find a damaged truss
The truss industry’s jobsite guidance, BCSI-B5 from SBCA and the Truss Plate Institute, sets out the order, summarized here:
- Brace or shore the truss so the damage does not spread and nobody is hurt, taking the load off it if it is already installed.
- Report the damage to the truss manufacturer straight away; SBCA suggests sending a photo so it can start on a repair or a replacement.
- Do not repair the truss without a repair detail from the building designer, the truss designer or the manufacturer.
- Follow that detail exactly, with the materials it specifies, and keep it in case the building official asks for it.
- Do not reuse a detail drawn for a different truss or a different break, and go back to the designer if the repair cannot be done as drawn.
SBCA’s point is that nobody, however experienced, can look at a damaged truss and know how it will perform, because a truss does not share load evenly like the links of a chain. The answer sits in the design software and drawings for that truss.
How a truss repair is designed
A Simpson Strong-Tie engineer, formerly technical director of the Truss Plate Institute, sorts repairs by the age of the trusses. New trusses are the easiest: the manufacturer can open the design, check the field condition and issue a repair. On recent trusses, another design professional can often work from the truss drawings and the plate maker’s published data. On old houses the drawings are usually gone and the plates may be impossible to trace; the Truss Plate Institute had 14 plate makers as members in 1987, and by 2015 only one of them was among the five left.
Standard details exist only for simple repairs. MiTek, one of the plate makers, publishes a library of them, covering jobs such as broken chords and webs, damaged or missing plates, a broken overhang, and broken or missing studs in a gable truss, each for use as drawn. Anything more involved is designed case by case, typically with plywood or OSB gussets or lumber scabs fastened to a calculated nail or screw pattern.
Roof truss repair cost
HomeGuide prices a broken roof truss repair at $500 to $5,000. The other costs that can come with it:
| Item | Cost |
|---|---|
| Broken roof truss repair | $500 to $5,000 |
| Structural engineer to inspect roof framing | $150 to $600 |
| Engineer’s inspection and plan for a sagging roof | $300 to $1,000 |
| New wood truss, material only | $60 to $500 |
| New steel truss, material only | $150 to $700 |
| Removing an old truss | $30 to $50 each |
| Crane to set trusses | $200 to $700 a day |
| Framing carpenter | $30 to $80 an hour |
| Roofing permit for framing work | $150 to $500 |
| Interior ceiling repair | $500 to $2,500 |
| Roof decking, per 100 sq ft | $200 to $500 |
The repair, sagging, ceiling and decking figures are from HomeGuide’s roof repair guide of February 9, 2026; the engineer, truss, removal, crane, carpenter and permit figures from its roof framing guide of June 5, 2024. That framing guide’s summary gives $60 to $500 a truss, the wood range, while its table runs to $700 for steel. Replacing all the truss framing costs $5 to $14 per square foot installed, $4 to $10 of it materials, or $10,000 to $28,000 for a 2,000 square foot roof, before the roofing that goes back on. The roof truss calculator counts how many trusses a roof has, and our roof repair cost guide prices the rest of the damage.
Repair or replace the truss
A repair is not always the cheaper route. SBCA notes that sometimes a replacement truss is the most efficient answer, and that the choice gets harder and dearer once the sheathing is on or the wiring, plumbing and ductwork are in the way. Two kinds of damage usually end in replacement. After a fire, sustained heat can leave hidden damage in a truss that looks sound, and after a collapse, trusses next to the broken ones may have been overstressed without showing it; the Simpson Strong-Tie engineer advises weighing the cost of a full inspection against simply replacing the trusses. HomeGuide adds that severe sagging can call for a full roof replacement rather than a repair, and lists age, severe water damage, termites and poor construction among the causes of structural problems.
Truss uplift: ceiling cracks that are not damage
A crack where the ceiling meets an inside wall can come from truss uplift rather than damage. Building Science Corporation explains uplift as a moisture difference between the chords: in an insulated roof the top chords are cold and the bottom chord warm, and the difference makes the truss move, lifting the ceiling at interior walls. Its report is blunt that uplift cannot be prevented, only accommodated.
The fix is in the drywall, not the truss. BSC recommends floating the corner: no ceiling drywall screws, nails or adhesive within 18 inches of the top plates of interior walls, with clips supporting the drywall so the ceiling can flex instead of cracking. If the roof line also sags, treat it as a sagging roof, which starts with an engineer.
Cutting trusses for attic space or equipment
Webs crossing the attic are what make a truss work, so removing them for storage, an access hatch or ductwork needs the same approval as any other alteration. MiTek’s library includes details for jobs like widening the space between two trusses for an attic access opening, but only for the trusses they were drawn for. If you want usable attic space, an attic truss, designed with an open room between its webs, is the way to build it in; our rafters vs trusses guide compares the options.
What this guide does not give
- A diagnosis. Only someone who has seen the truss and its drawings can say whether and how it can be repaired.
- Repair details. They are specific to each truss and come from the designer, not from a website.
- Insurance outcomes. Whether a policy pays depends on the cause; our insurance guide covers how claims work.
Sources
- 2024 International Residential Code, Chapter 8, Sections R802.10 and R802.10.4: truss design, drawings and alterations.
- SBCA, Trusses Damaged? Here’s What To Do, Frame Building News, November 2021: the BCSI-B5 steps and when to replace rather than repair.
- Simpson Strong-Tie, Truss Repair Information: The Never-Ending Search, June 2015: how repairs are designed for new, recent and old trusses, and fire and collapse damage.
- MiTek, Roof Truss Repair Details: the library of standard repair details.
- Building Science Corporation, RR-0107: Drywall, Wood and Truss Uplift, 2001: the cause of truss uplift and floating corners.
- HomeGuide roof repair cost guide, dated February 9, 2026: broken truss, sagging roof, ceiling and decking repair costs.
- HomeGuide roof framing cost guide, dated June 5, 2024: truss, engineer, removal, crane, labor and permit costs.
- All read on November 4, 2026. The 2,000 square foot example is our arithmetic. Every source is listed on the methodology page.
Related calculators and guides
Roof truss repair FAQ
How much does it cost to repair a roof truss?
HomeGuide puts a broken roof truss repair at $500 to $5,000. A structural engineer to inspect the framing adds $150 to $600, a new wood truss is $60 to $500 for the material and a steel one $150 to $700, and any ceiling repair below runs $500 to $2,500.
How do you fix a broken roof truss?
With a repair detail drawn for that truss by the truss maker, a truss designer or an engineer. Typical repairs add plywood or OSB gussets or lumber scabs fastened to a designed pattern, or replace the truss. Until then, the truss is braced or shored to take the load off.
Can I fix a roof truss myself?
Only by following a repair detail designed for it. The industry's BCSI guidance says not to attempt a repair without one, and the IRC bars altering a truss without a registered design professional's approval. A detail made for a different truss or a different break should not be used.
Is it better to repair or replace a damaged truss?
It depends on the damage. SBCA notes that a replacement truss is sometimes simpler than a repair, especially before the sheathing goes on. For fire damage or a collapse, truss designers often recommend replacement, because heat and overstress can leave damage that cannot be seen.
Can you cut a roof truss for attic space or ductwork?
Not without approval. Section R802.10.4 of the IRC says truss members must not be cut, notched, drilled, spliced or otherwise altered without the approval of a registered design professional, and that equipment loads such as an HVAC unit cannot be added without checking the truss can carry them.
What is truss uplift?
The bottom chord of a roof truss lifting in the middle and pulling the ceiling up off the inside walls, leaving a crack at the corner. Building Science Corporation explains it as moisture differences between the cold top chords and the warm bottom chord of an insulated roof, and says it cannot be prevented.
How do you fix truss uplift cracks?
By letting the truss move rather than fighting it. Building Science Corporation recommends floating the ceiling corner: no ceiling drywall fasteners or adhesive within 18 inches of interior wall top plates, with clips holding the drywall so it can flex instead of cracking.
Can fire-damaged roof trusses be repaired?
Sometimes, but designers often recommend replacing them. A Simpson Strong-Tie engineer writes that most truss designers they have spoken with recommend replacement after a fire, because sustained heat can leave hidden damage, and that the cost of a full inspection should be weighed against the cost of new trusses.
Who designs a roof truss repair?
The truss manufacturer or the truss designer when the trusses are new, since they have the design files. For older trusses, an engineer works from the truss drawings or models the truss, and may need to identify the metal plates, which gets harder the older the house.
Do you need a permit to replace roof trusses?
HomeGuide says a roofing permit, $150 to $500, is required when replacing roof framing. The truss drawings for new trusses also go to the building official for approval under the IRC.