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How Are Sagging Floors Fixed?

Thursday, April 15th, 2021
sagging floors

Sagging floors are usually a visible sign of deteriorated structure somewhere below. In many cases, the factor causing this deterioration is water damage originating from above—such as severe indoor flooding— inside the crawl space. Chronic moisture in basements may also affect floor structure. Two components of the floor may be affected by sagging:


These are the wide wooden panels that lie directly below your flooring. Typically standard plywood or OSB (oriented strand board) subfloors can be affected by water damage inside the house due to flooding, ruptured pipes, or other causes. If water is present long enough to seep through flooring and saturate the subfloor, sagging may occur in spans of subfloor between the supporting joists beneath.  


Joists are wood beams, evenly spaced and running parallel to each other beneath your floor structure. Joists are vulnerable to water damage due to flooding in the crawl space from outdoor sources such as heavy rain or from chronic leaks in plumbing pipes routed through the basement. Water-related deterioration causes joists to weaken, resulting in sagging floors above.

Fixing Sagging Floors

In many cases, water-damaged subfloors must be entirely removed and replaced with new wood. However, if a wet subfloor is quickly opened up—flooring, tile, or other material removed—before it has absorbed too much water, and the material subjected to continuous drying processes by qualified water damage professionals, the wood may be effectively saved and sagging prevented. Once subfloor panels are fully saturated for any length of time, however, replacement of the affected wood is often necessary to prevent sagging floors and other deformation.  

Two methods may be applied to deteriorated floor joists that cause sagging floors. “Sistering” is a procedure where a sagging joist is jacked up to level, then a new, fully intact joist board is attached to the existing joist to straighten it and restore structural stability. Where the original board is not severely deteriorated, this eliminates the need to remove existing joists. Alternatively, multiple jacks may be utilized to level sagging floors, then each existing joist is removed and replaced with a new board.

Repairing Water Damaged Wood

Tuesday, June 23rd, 2020
water damaged wood

Unlike some building materials, wood can be particularly susceptible to water damage. Cellulose fibers in porous wood absorb moisture quickly and dry very slowly. Staining also occurs and wood may be contaminated by saturation with raw sewage or toxic floodwater. Swelling and warping may permanently distort wooden materials.

The most vulnerable wooden materials with substantial value are typically hardwood flooring and wood paneling. In most cases, DIY methods are not sufficient to remedy significant water damage. Rapid treatment by qualified, equipped professionals is necessary to save or repair wood floors and wall coverings. Here’s a summary of what’s involved.   

Hardwood Floors

Action must begin as soon as possible following water damage to salvage affected hardwood floors.

  • Wet/dry vacuums and powerful extractors can remove pooling water and suck moisture out of the flooring. This may prevent saturation of the subfloor beneath.  
  • Air drying utilizes high-volume fans that direct airflow across the floor. Industrial dehumidifiers also accelerate drying.
  • If water has penetrated below flooring, portions or all of the floor require removal in order to dry the subfloor beneath and prevent wood rot and mold growth.  
  • Hardwood flooring planks may cup, warp, or buckle during drying. Sanding may restore a flat surface. If distortion is significant, however, affected planks will have to be replaced.
  • Sanding and re-staining may be required to erase stains caused by water damage.

Successfully drying hardwood flooring after water damage is very time-intensive. Several weeks of continuous air drying and humidity reduction may be necessary.

Wood Paneling

If wood paneling is affected by water damage, the wall structure behind it is likely wet, too. Wet paneling must be removed to access the drywall and internal wall cavity. Saturated drywall requires replacement and the wall cavity must be dried and disinfected to prevent mold contamination.

Some wood paneling may be successfully dried without warping if the drying process is slow and natural. After removing the baseboard, individual panels can be taken down and wiped clean with disinfectant. Panels should be separately placed upright, away from direct sunlight, HVAC vents, or other factors that might accelerate drying and induce warping.