Adding new space to your existing house may be a great idea. However, knowing exactly where your property boundaries and relevant setback lines are located is an essential part of planning for a new addition to any home. Do not just guess. The outcome of such a decision may not be desirable.
We have encountered two instances recently where the owners and contractors did just that. In both instances, city or county officials stopped work on the projects. In Example 1, the existing house was already in violation of the setback, but the city agreed to allow the addition to come as close to the sideline as the pre-existing house. The footer had to be re-dug about two feet further from the property line. The entire addition was shifted over.
Unfortunately, in Example 2 (picture shown) the work stoppage came quite late in the building process. The new addition is very close to the property line (2.5 feet), violating a building setback line as well as a five-foot utility and drainage easement. The home owner is now completely at the mercy of zoning and planning authorities. It remains to be seen whether a variance will be granted or whether the homeowner will be forced to buy adjacent property. In extreme cases, the zoning authorities may require the offending portion of the dwelling to be removed. We are awaiting the verdict of officials now. Either way, the project is subject to long delays and additional unforeseen costs. Even if a variance is granted, who wants their house to have a 2.5 foot side-yard? I imagine that condition may be a deterrent to future buyers as well.
Take care. Plan ahead. Do the due diligence of getting a survey and save yourself a lot of headaches.