**** that looks a lot like my barn on the inside. I've even done some of the same repairs on the same pieces. What sort of milling marks do you have on your beams? You can kind of date a barn by how the beams were cut, whether they were hewn with an ax, cut with a straight saw or cut with a rotary saw. My barn has even straight saw marks, which indicates they were cut by a water-powered mill, probably shortly after the Civil War. Rotary saws started appearing after the Civil War and really got popular when steam power and then electricity came along.