You can build an outbuilding as close as you want to your house, but there are some things you should keep in mind. Building codes vary from place to place, so it's important to check with your local government to find out the specific regulations in your area. In general, however, most outbuildings must comply with the same setback requirements as houses. This means that they must be located a certain distance away from the house, depending on their size and height. It's also important to make sure that your outbuilding is well-ventilated.

You can build an outbuilding as close as you want to your house. However, you should always check with your local municipality to make sure there are no restrictions or setback requirements.