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You should consider replacing your floor joists if you notice moist or rotting wood, uneven door and window frames, sagging floors, or cracks in interior drywall. Also, check your crawl space for tilted or sinking supports. If you observe any of these signs, contact a home inspector for an assessment.

Technically yes, you can replace a floor joist without removing the flooring, but only if your joists are accessible. For example, in an unfinished basement or crawl space, you can often see exposed joists in the ceiling, making it relatively easy to replace them. However, if your joists are insulated or covered by flooring and subflooring, a pro must remove them before making repairs.

A single cracked or undersized floor joist can be effectively repaired using the sistering method. This repair method involves raising the floor frame in measured, precise increments to allow the installation of a new, reinforced joist alongside the damaged one. The method is essential for restoring structural stability when the joist’s integrity is compromised, and a skilled professional ensures that the added beam is accurately aligned to support the full load of the floor.

Floor joists properly installed in a stable environment can last for 100 years or more, so they often last as long as a house lasts. However, termite damage, moisture and leaks, and other problems can significantly lower a floor's lifespan. For instance, if the floor is exposed to consistent moisture, you'll likely need to replace the joists every 20 to 30 years.

Homeowners insurance does cover floor joist damage when it stems from sudden, accidental events such as a fire, windstorm, or water damage due to a burst pipe. This protection does not extend to repairs needed because of gradual deterioration, insufficient maintenance, or termite infestations. It is essential to review your policy and consult your insurance provider to determine the specific conditions that qualify for coverage so you can plan your repairs with confidence.