Encroachment is when a structure has been placed on your property by mistake.
For example, your neighbor puts up a new fence, and you find out it is sitting three inches on your property.
A survey will determine property boundaries and if an encroachment exists.
A minor encroachment normally will not affect your loan.
Encroachment also refers to the gradual displacement of an existing use by another use. Any encroachment issues are usually addressed with appraisal and title.
Finding out about encroachment at appraisal or title time is a good thing. It could save you lots of headaches down the line if it is not caught early enough to be addressed.