Commercial Janitorial Service. Diamond Building Maintenance is a superior janitorial service with clients throughout the Salt Lake City, Utah area. We can clean single office or entire buildings. Our trained cleaning technicians are committed to doing the job right and your satisfaction is guaranteed. Diamond specializes in: • Carpets • Floors • Carpets • Walls • Windows We are licensed, bonded and insured. Of course, references are always available. Payment can be made by cash or with most major credit cards. Call today for a free estimate or to schedule service.