In selecting the right size cupola for your building, a good rule of thumb is one and a quarter inches (1.25") of cupola base for every foot of unbroken roof line. The key idea here is the unbroken roof line measurement.
For example, if a roof section measures 20', the minimum cupola base should be 20". However, we usually suggest the next size larger. Our experience tells us it provides for a more pleasing appearance. If the cupola is too small, it will look like a bird house. In fact we recommend going one or two sizes larger, especially if there is significant height to the structure, or an adjoining building.
