Unevenness

• Unevenness affects many wood floors and is caused by unevenness in the foundation or joists. Unevenness can be cured by repairing the slab or joists. In some cases, it may be necessary to add more joists to stabilize the subfloor. If the issue stems from a cracked slab, you will need to hire a contractor to complete the project. While doing this will correct most problems with unevenness, some unevenness is natural seasonally and should be tolerated.
  
  

Warping

• Warping problems are classified by type. Cupping is a warped slat that dips in so the edges are higher than the center of the board and is caused by a greater amount of moisture on the bottom side of the board. Buckling is a warp caused by an extreme moisture problem or insufficient nailing. Crowing is a type of warp identified by an upward bowing of the slat and is caused by moisture imbalances on the finished side. Crowning can also be created from an improperly repaired cupping problem. Warping problems are cured by addressing the moisture problems that caused them. Humidifiers can be used to control many atmospheric moisture issues. Once the moisture problem is identified and corrected, you can use countersunk nails, putty and sanding to correct the flooring problem.
  
  

Stains

• A number of liquids and materials can stain wood flooring. The most common staining is from water. Areas around windows and plumbing fixtures tend to suffer the most from this problem. Stained areas on floors will need to be treated with a equal mixture of bleach and water, then refinished to correct the problem. In extreme cases, it may be necessary to sand the area down to the bare wood and stain again. If the stain is too deep or large, it may be more cost and time effective to replace the affected boards.