Floor Joist Repair and Sistering
A cracked, notched or rot-weakened joist can make a floor bounce or sag. Sistering bolts or screws a new joist alongside the old one so the pair carries the load again. We fix the cause too, whether it is moisture, a notch or a missing support, so the repair lasts.
- MethodNew lumber fastened alongside
- FastenersStructural bolts or screws
- FixesCracks, notches, sag
- Pairs withMoisture control
What is included
- 1Stronger floorsJoists carry load again.
- 2Less bounceFloors feel solid underfoot.
- 3Cause fixedMoisture or notching addressed.
- 4Clean workNeat, well-fastened lumber.
From the first call to a dry crawl space
Our partner experts repair and protect crawl spaces in cities across the country. Find yours below and ask for a free estimate.
- 1AssessWe find weak joists and the cause.
- 2FitNew lumber is cut and set alongside.
- 3FastenStructural fasteners go in.
- 4CheckWe re-measure the floor.
Is this the right service for you?
- A floor that bounces or feels soft
- A visibly cracked joist
- Owners after plumbing cuts in the joists
- A home with sagging near the middle
Common questions
Is sistering a permanent fix?
When done right and the cause is fixed, yes. Moisture control keeps it that way.
Do I need an engineer?
For larger problems, sometimes. We tell you when.
Will the floor be level afterward?
Often improved. We explain what to expect.
Services that pair with this one
Sagging Floor Repair and Support JacksAdjustable steel jack posts on solid footings lift and hold sagging floors in place.See the service 
Wood Rot RepairCut out the soft wood, fix the moisture and fit new lumber so the rot does not come back.See the service 
Structural Damage AssessmentSagging floors, soft wood and cracked piers, checked and explained before anyone starts cutting.See the service Find your city
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Call or text, or send the form for your free estimate. Tell us what you notice, from smells and cold floors to water and sagging.