If the floor boards weren't cured properly before they were installed, cracks will appear at the ends of boards or between the boards. These can often be filled with wood putty and sanded smooth. Use a soft wire brush to clean out the cracks before filling.
Burns and Spots
Surface burns, such as cigarette burns, should dissappear when the floor is sanded. Spots of oil, wax and grease can be removed with turpentine. However, boards with deep burns will need to be removed and replaced.
Loose Boards
If the hardwood floor is buckled or has lifted up from the subflooring, you will need to reattach it. Ring shank nails should be used, nailing through predrilled holes, which are angled toward each other. This helps the nails hold better. Countersink the heads and fill with wood putty.
Sags
A sagging floor often results in sticking doors and windows, cracked plaster, sloping floors and even leaky roofs. The result is the floor cannot support its own weight. A sagging first floor will affect any floors above it, but upper floors may sag without the first floor being affected.
If your floor sags, you should have a professional builder inspect the floor to determine the cause. Sagging can be caused by joists warping as they dried, the wrong sized lumber used for joists, cracked or rotten joists, termite damage, or by joists being spaced too far apart. The cause may also be more severe in nature. The foundation may be crumbling under the ends of the joists or settling unevenly. And if the second floor sags, you will need to remove the ceiling on the first floor to get to the problem.
If you have sagging floors and choose to do the work yourself, at least have a professional builder inspect the problem and go over the needed repairs with you. Then you will be better able to decide if you are up to the challenge.
Squeaks
I have yet to walk across the floor of an older home and not find a squeak. A squeak is the result of a problem with the floor structure. Some common structural problem are floor joists spaced too far apart, not enough nails being used when the floor was laid, or the wood not being
