A Little Water Usually Hurts

• A few inches of water on a road can sweep away large vehicles. A few inches of water on a hardwood floor can damage it irreparably. Hardwood naturally expands and contracts with changes in humidity. If it is exposed to too much water for too long, it will permanently warp. Even a water spill that rests on hardwood too long will ruin the planks.
  
  

Self-Correcting Wood

• A hardwood floor that experiences minor damage -- especially from everyday incidents, such as a spill that went unnoticed for a few days -- might flatten back out on its own after it has been cleaned and thoroughly dried. However, with severe damage -- such as with floods -- that drying process can take weeks if not months. Wide pine boards are the most likely type of wood flooring to correct itself once dried even after a flood.
  
  

Check the Subfloor

• If a hardwood floor is severely damaged from flooding, examine the subfloor. Many homes' subfloors are constructed of plywood, which will separate when exposed to too much moisture. If that -- or any other -- subfloor is damaged, it must either be repaired or torn out and replaced before attempting to repair or replace any hardwood floor on top of it.
  
  

Patience Is Paramount

• Hardwood and damaged subfloors must be cleaned and thoroughly dried before any repairs are attempted because wood shifts -- expands and contracts -- as it dries. Any repairs completed before the hardwood -- or any subfloooring giving off moisture -- has thoroughly dried will simply be negated by the wood's movement as it adjusts. This process can take weeks or months, depending on the severity of the damage. Turning on a furnace while the floor is drying will speed up the process.
  
  

DIY Repair Techniques

• If a hardwood is obviously severely warped, it's probably not worth saving, according to the Michigan State University Extension. However, if only minor warping remains after the wood is dry, you can remove strips adjacent to buckled boards and plane the edges, which gives the buckled boards room to flatten out. For humps, nail them down or plane, sand and refinish them. If these methods don't work, replace the damaged portions in an attempt to save the floor. Longstrip planks are particularly easy to replace, versus engineered and solid hardwood.
  
  

Reusing the Floor

• If severely water damaged hardwood has been cleaned, dried, planed and sanded and yet is still not salvageable as a functional floor, it might make a perfectly viable subfloor. Contact a reputable contractor to help determine if damaged hardwood can be repurposed in this manner.