Can new flooring be installed over the old flooring boards, particularly if there is no existing sub-floor in place at this time? In effect the old flooring would become the sub-floor. The existing floor boards are about 3.5 in. wide.
If it's not a problem to simply put the new floor down over the old, I would assume that at least you would never run the new flooring parallel to the old, but would have to install at either 90 or perhaps 45 degrees to the existing boards.
And isn't tar paper often laid down over the sub-flooring, to minimize squeeks?