Structural repair: what to know

What the job involves, what changes the price, and what to ask a pro.

What structural repair is

Structural repair reinforces or restores load-bearing parts of a building, such as beams, joists, posts or framing that have been damaged by rot, pests, settling or past alterations. The work uses sistering, steel or new members, and it has to be designed so the building carries its loads again.

Signs you need it

  • A floor bounces, slopes or feels soft between two points, or a joist shows cracks, rot or crushing at the bearing end
  • A beam or post has split, rotted at its base or been notched by a past remodel
  • A wall is sagging, bulging or pulling away from the roof or the floor above it
  • Doors and windows have started to bind or crack in a new pattern, which can mean the frame is moving
  • Termites, carpenter ants or water damage have reached the framing, and the damage is visible from the crawl space or the attic

What the pro does

  • A structural engineer or a qualified contractor inspects the framing, measures the damage and identifies the load path
  • They shore or temporarily support the affected members before any removal, so the rest of the structure does not move
  • They remove the damaged material and check the connections and the bearing points that remain
  • They install the repair, such as a sistered joist, a new post, a steel beam or a new header, to the engineer's design
  • They check the repair for fit, bearing and fastening, and remove the temporary supports only after the new members are carrying load
  • They document the repair with photos and the engineer's letter, and address the cause, such as moisture or pest activity

What changes the price

Every job is different, so we do not publish prices. These are the things that move the quote up or down.

  • Number and location of damaged members, and whether they are in a wall, a floor, a roof or a foundation area
  • Type of member, from dimensional lumber to engineered beams or steel
  • Length and span of the repaired members, and the loads they carry
  • Access to the damage, including crawl spaces with low clearance, attics and finished walls
  • Temporary shoring needed while the repair is made
  • Engineering design, inspection and permit requirements for the repair
  • Finish work to restore drywall, trim, flooring and the cosmetic surfaces after the repair

What a written quote should spell out

  • Scope of members to be repaired or replaced, with sizes and grades listed
  • Engineering design and stamp, with the engineer's name and what the letter covers
  • Temporary shoring method, its location and how long it stays in place
  • Connection hardware, fasteners and bearing details for each new member
  • Permit, inspection and the stages each must pass before the work is covered
  • Cause remediation, such as moisture control or pest treatment, if it is included or priced separately

Questions to ask before you hire

  • Has an engineer reviewed the damage and designed the repair, and will they stamp the design?
  • How will you support the structure while the damaged members are removed?
  • Which members are being sistered and which are being replaced, and why?
  • Does the repair address the cause of the damage, such as water, termites or overloading?
  • Will the permit and the inspections be done before the new work is covered?
  • Who restores the walls, floors and finishes disturbed by the repair?
  • What warranty do you give on the repair, and does the engineer's design support it?

Red flags

  • They cut or remove a load-bearing member before the building is temporarily supported
  • They sister a joist or a beam with no engineering review on a span that clearly needs it
  • They fix the damaged framing and leave the water or the pests that caused it
  • They will not provide the engineer's letter or the permit records for the work

What you can do yourself

Do not attempt structural repair yourself. A damaged beam, joist, post or wall can fail without warning, and removing or cutting a load-bearing member can bring down part of the building. Keep the area clear, photograph the damage and note when you first saw it, then call a licensed contractor and a structural engineer.

Licenses and permits

Structural repair is often done by a licensed contractor and commonly needs a building permit and an engineer's design and stamp, because it changes or restores load-bearing parts. Check with your state or local licensing agency and your local building department for the permit and engineering rules that apply to the building.

Structural repair questions

Can a sagging floor be fixed without an engineer?

The cause decides the fix. Sagging can come from rot, undersized joists, a failed beam or a settling foundation, and each needs a different repair. An engineer should confirm the cause and the design before any member is changed.

Is a sistered joist as good as a new one?

It can be, when the sister is sized, fastened and bearing the way the engineer specifies. A sistered joist does not fix the cause of the damage, so the moisture or pest problem must be corrected as well.

How do I know if a crack in a beam is dangerous?

Any split, crushing or rot at a beam end or bearing point needs a professional look. Do not load the beam or try to brace it yourself, and call a structural engineer or a licensed contractor promptly.

About this guide

This national guide is written and checked by infinibell. Rules and conditions differ by place, so local pros are credited on guides for the cities they serve, not on national ones.

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