I have another house on the eastern shore of Virginia, and the land over there is mostly on sea level or just above. The foundation to the house over there (built in 1869) was sinking ever so slightly. I never noticed until the door started looking like your door. So, perhaps the foundation of the house is sinking or the board to support it are rotting?
It is all possible.
Still, in all, I think it has lots of character! :)
Upped and Steemed
Thank you, Denise! Yes I also think it's the foundation that is sinking, you even can see it on the pavement in front of the houses that they seem to be leaning on each other.
It wouldn't be a huge problem if these things were fixed as soon as it happens! But, like the people who owned our shore house, just left it and it continued to deteriorate! (We have since fixed it)
Hope you are having a splendid day! ;)