If your neighbor starts building on your land, don’t just ignore it. It could eventually become a problem when you try to sell your house. A title company may refuse to issue insurance because the neighbor is on your land. If the situation is not taken care of immediately, after a certain amount of time the neighbor can gain a legal right to continue building on your land. In some situations, this may lead to them gaining ownership of that piece of your property. Discuss the problem with your neighbor immediately. If your neighbor insists on proceeding and you decide to sue, have a lawyer send a letter on company letterhead stating your intent to sue. If your neighbor is not deterred, have a lawyer get a judge’s order to temporarily stop the neighbor until you can bring a civil lawsuit for trespassing on your property.