Encroachment question

[JenB987]

What is the name of your state (only U.S. law)? PA

Our home and the neighboring house have been in my husband's family since their conception. The neighboring house used to be his grandparents' and when they passed, left it to my husband's uncle. To make a long history on the neighboring house short, his uncle got a divorce, and left the home to his ex-wife. Our house used to be my in-laws house. They sold it to us in Jan. 2007. My husband lived in our house his entire life. (28 years)

My husband's aunt (the ex-wife of the uncle) lived in the house up until Dec. 2005, when her family up and left. It soon was up for sheriff's sale with no takers. During the time we were closing on our home with my in-laws, the house next to us was vacant.

Being that these two homes were never out of the family, the property lines were more or less "understood". When we closed on our house, we didn't get a survey done because nothing on the property has changed in 35 years--the age of our house.

During the summer, we found out the neighboring house had gone into HUD, after almost 3 years of it being vacant.

Now here's where my problem lies. There is a 300 sq. ft. piece of land that is owned to the property next door, but my husband maintanenced the entire property to that house, including the land closest to our house, even when his aunt/uncle lived there. We also found out that our split level porch and vestibule are on the neighboring house's property. Someone is buying the house and had the survey done last week, which is how we found this out.

We know that we should have had a survey done when we bought our house, but being as which no one occupied the house next door, nor could we find out who still owned, we figured there was nothing we could do anyway.

Would any of this fall under a grandfather clause or adverse possession?