A long tape is typically a tape measure that is at least 100 feet (30.48 meters) long. The average tape measure used on a construction site is 25 feet (7.62 meters) in length. There is usually a long tape carried in the job box or tool box that is used when a long measurement needs to be taken. Difficult measurements, such as squaring a wall or a floor, are accomplished by using a long tape to cross-measure the structure. Due in part to the infrequent use of a long tape, the tape material is usually fiberglass instead of the typical metal in order to prevent rust and sticking when the tape is pulled out.
Rather than using an automatic spring retrieval system similar to those used on smaller tape measures, the long tape uses a hand crank that allows the operator to wind the tape in when finished with a measuring task. This is done, in part, due to the size of the spring a 100-foot (30.48 meters) tape would require to automatically wind it back up. The speed generated by a long tape winding automatically would also be dangerous to the user. This speed could also potentially damage the tape, rendering it useless on the job site.
The earliest versions of the long tape were constructed using a cloth tape. This type of tape allowed a slight amount of stretching, which would lessen the long tape's degree of accuracy. Aside from stretch, water would also permeate the tape, creating a heavy tape that would sag and alter the measurement. The inability of a cloth tape to register correct readings on a consistent basis led to the development of the fiberglass tape.
By implementing a fiberglass tape into the long measuring device, accurate measurements can now be taken even underwater. The use of a metal tape would not allow this type of measurement without causing the tape to eventually rust and become unusable. Improvements in the tape's case design have made rust and corrosion a thing of the past. Heavy plastic and fiberglass have been merged with space-age polymers and alloys to construct a tape measure case that is nearly impervious to damage by the elements of nature.
In the construction industry, there is no substitute for accuracy. Measurements are perhaps the single most critical step in the construction of any project. When making measurements on a very long span, using a short measuring tool over and over again will not give as accurate of a measurement as using a single long tape.