There are different grades of hardwood used starting at 3rd grade being a lower grade and 1st grade being the highest grade of wood available; the difference is the choice of the owner and what they want their floor to look like; 3rd grade wood has many imperfections where 1st grade wood’s imperfections are at a minimum. The subfloor systems vary depending on what purpose the hardwood floor is for. Basketball gymnasium sub-floors allow for more impact than a Racquetball/Squash/Handball Court.
