Wood floors are a good way to increase the property value of a house. Wood, however, must be protected from the elements. When wood gets wet it swells and when it gets dry it shrinks. Wood that is constantly wet is prone to rot, mildew, and mold damage. Wood floors that are damaged by water need to be repaired or replaced.
The first thing that needs to be done is to figure out what is causing the water to make contact with the wood floor. If you fix the floor before fixing the water source, you are simply delaying more damage. Flood water damage is the easiest to figure out, but there are many other causes. Is the roof leaking? Is there a pipe leaking in the wall? Is the water coming in from outside? Everything that could be a possible culprit needs to be checked out.
Once the source of the water damage has been located, it needs to be repaired. There are very few possibilities that are cheap to fix. Hopefully you've got a clogged gutter or something simple and cheap to repair.
While some water damage causes can be done by the homeowner, many will require professional help. Whether that help is a roofer, a plumber, or someone to re-grade the slope away from the house all can cause some serious cash flow problems.
Once the cause of the water damage to the wood floor has been found, the floor can be either fixed or replaced. If the water is caught early enough and the damage is mostly cosmetic it is possible to buff and polish the damaged area. It is important to check the underside of the wood floor for soft spots which could indicate rotting.
Replacing a wood floor or sections of a wood floor can be done by a handy homeowner or by hiring a professional installer. There some pretty easy DIY wood flooring options available in the local home improvement stores. Some of these stores even offer classes that teach people how to install the flooring themselves.
Hiring a professional will cost more, but if the homeowner hasn't a clue how to start, they may be the best option. If you've never done this sort of home improvement project, starting with an expensive flooring project might not be the best idea.
It is much cheaper to not have your wood floor damaged by water in the first place, so protect your floor by cleaning spills as they happen, and watching for leaky things.