An encroachment is the illegal use of another person’s property without prior authorization.

In a real estate transaction a contract may be voidable if the title becomes unmarketable due to an unknown encroachment and a contract for sale has been executed before a survey reveals that an encroachment does exist. This situation usually exists when a structure, such as a fence or shed, is built in whole or part on a neighboring property.

Encroachment boundaries are usually displayed or marked on the survey by fences, ditches, hedges or trees. Encroachment mistakes can be caused by incorrect survey, mistakes or miscalculations by the builder or owner when building a home. 

If you have an incorrect survey it can be corrected by giving or selling the encroaching party an easement or lease for the lifetime of the structure, actually moving it onto the owner’s own property.