Covered bridges are generally considered old-fashioned, and appeal to tourists, but the purpose is twofold: (1) covered bridges appear similar to barns and it is easier to transport cattle across them without startling them, and (2) to build a structure for weather protection over the working part of the bridge. A bridge built entirely out of wood, without any protective coating, may last 10 to 15 years. Builders discovered that if the bridge's underpinnings were protected with a roof, the bridge could stand for 70, or even 80 years. The existing covered bridges have been renovated using concrete footings and steel trusses to hold additional weight and to replace the original support timbers.Some covered bridges, such as the one in Newton Falls, Ohio and Elizabethton, Tennessee, also feature an integrated covered walkway.
