While there is no mandate that it must match and for casement windows you will pay a little more, the design continuity will pay dividends on your resale value and appreciation. 30-degree bay windows are 12 to 14 inches deep, and a part of your home improvement, there are several different choices. I will respond with a step by step answer on how to complete your home improvement project along with a list of any special home improvement tools that may be required. I have been a construction contractor for over 15 you and family and possibly future families the enjoyment of your design choices