It can be easy to patch cracks in an old wood floor or grout a new wood block floor. Here's how. First, make a mixture of two part sawdust with one part fast-drying, oil-based sealer. Squeegee the mixture into the cracks of your floor. Wipe off any excess with a steel wool pad, so the floor is clean and smooth. Let it dry overnight and then apply the finish coat of your choice.
For more on flooring, consider:
Fixing Squeaky Floors (VIDEO)
Old Wood Flooring: Replace or Refinish?
Selecting Engineered vs. Solid Wood Flooring