I am considering a house to purchase, but it has 1/4" oak flooring that someone "refinished." They clearly did not sand the wood, as they are irregular in color, etc. I have refinished thousands of sf of flooring, all of which I sanded to bare wood. These floors, however, are already coated with polyurethane varnish and I'm wondering if I sand them if they will act like shellac and melt, clog the sanding belts, etc.
It is a 50 year old house, and these are the original install wood, not an engineered product. Solid wood, but with the finish poorly done.
What is the best way to proceed to get properly down to the bare wood?