Cedar Rapids, IA Windows, Doors, Siding and Garage Doors Cedar Rapids is the second largest city in Iowa with a population of over 126,000 people. That means there are a lot of homes that may need replacement windows, siding and doors. Feldco has a location in Cedar Rapids to help the homeowners with their home improvement needs. With over 400,000 happy customers, 40 years of experience and high quality products, you know your window, siding or door replacement is in good hands with Feldco.