1800's farmhouse, but don't know how old the flooring is. Regular wood flooring (not plywood) but might have been cheaper wood. Doesn't look too bad considering the age. Doesn't look like it was ever varnished or sanded or anything. 1/16th or a little larger gaps in between and dirt has accumulated. Can this be removed, wood filler applied, sanded and then refinished possibly? Or, is it better to use it as a subfloor for something else. Doesn't squeak but because of age of house the floor appears to slant or warp but that might also be because of the temperature here in Michigan. Hardly noticeable unless you're really looking for it. Thanks for any suggestions.