Using an oil based polyurethane over Zinsser finish

Q: We have 150 year old red oak floors with several coats of Zinsser Target clear epoxy based finish on them. We have been unable to find the same product and are thinking of using an oil based polyurethane over the existing finish.

Will it stick and not bubble or peel? What kind of prep is need prior to application?

A: I’m afraid I have no experience with this product. I would recommend contacting Zinsser.

You might perform a test spot in an inconspicuous place in the room. Rub the spot well with fine sand paper and apply a coat of finish and see what happens.