Commercial building is driven both by business cycles and population growth. As more people move into a given area demand increases for existing work space. Schools, municipal buildings, retail stores, and offices become more fully occupied driving builders to build office and retail space to meet percieved demand. As the business cycle ramps up, new construction is ordered to provide space for workers and more frequent shoppers.
In today's commercial construction environment, many builders now specialize in a single commercial market. Some specialize in high-rize buildings, other hone their expertise in providing heavy infrastructure facilities like water treatment plants or dams. Still others may specialize in tilt slab construction. A certain amount of competitive advantage accues to those who have significant experience in a they type of commercial construction they are bidding on. In many areas this specialization can break down even futher with major parts of a construction project such as perimeter concrete fences being built by a company that specializes in building only this type of fence.
Builder's can smooth out inevitable work flow peaks and valleys by taking on projects to refit office space or other commercial buildings.