You've probably heard the old adage that says, "good fences make good neighbors." It comes from a poem by Robert Frost, and it's good advice if you ever want to sell your property. Unmarked boundary lines can result in your neighbor building either all or part of a new garage on your land.
You might not have a problem with this at first since it doesn't interfere with how you live on your property. However, if you put your property on the market, a potential buyer could take issue with the garage's position. For this reason, if you even slightly believe that you could sell, you may want to address the issue now rather than later. Of course, the best time to do so would be before the structure goes up, but you may not have fully considered future problems when it happened.
Do you know where your land ends and your neighbor's begins?
A legal term for what your neighbor did exists. Encroachment happens when another person erects a structure on your land. More than likely, when you bought your property, you knew where the boundaries were, but if you have lived there several years, those lines may have blurred. If you suspect the structure is on your land but aren't sure, the first step would be to determine exactly where your property ends and your neighbor's begins in order to avoid starting an unnecessary argument.
If it turns out the structure is on your property, it could preserve the peace to talk to your neighbor first before going to court. It may be possible to move the structure, but if it isn't, you will need to come with a way to resolve the situation.
What kind of arrangement could you make?
You could agree to leave the structure in place, and draw up a written agreement giving your neighbor permission to use the land it is on, which goes a long way toward preventing a claim of adverse possession in the future. If the structure, or encroachment, cannot be moved, or your neighbor won't move it, you still have another option. You could sell that portion of your land to your neighbor, but if you have a mortgage loan, you need to consult with your lender first.
If your neighbor won't cooperate
If there isn't much of a neighborly relationship to preserve, and the other party is uncooperative, you may need to take more formal steps by initiating litigation. To prevail in such a claim, you need to show a Texas civil court that you own the property and that your neighbor is using your land without your permission. If the court rules in your favor, your neighbor must remove the structure from your land.
The risk is that the structure has been there for too long, and the court could rule in favor of your neighbor who would then have the legal right to use the land in a limited capacity. For this reason, you may want to discuss your situation with an attorney before moving forward.