In the world of wood-frame construction, portable classrooms offer unparalleled strength. They are designed to be transported safely over long distances at highway speeds and lifted by crane onto a foundation. Major components such as walls and floors are fastened together with both nails and special adhesive with the adhesive providing a stronger bond than nails. Site built construction is typically only nailed together.

Portable classroom manufacturers employ several special techniques to strengthen the framing system at its stress points. For example, most manufacturers build their floor systems with a double perimeter band rather than the single band used by stick builders. This makes the floors exceptionally strong and rigid.

Since they are built on perfectly square jigs, the floors are also perfectly square. The structure of two-story portable classrooms is also strengthened by installing both floor and ceiling joists in all modules. Consequently, the first floor of two story portable classrooms has a ceiling that is independent of the floor of the second story above.

A stick-built two-story classroom makes the first story ceiling perform double duty as the second-story floor. In addition to making for a stronger portable classroom, the modular building method also helps reduce noise transfer between floors.

Many builders of portable classrooms use metal plates to join the tops of intersecting interior and exterior walls. In addition, they use steel straps along the bottom and top of each side of the marriage wall which is where the two modules join together.

This ties together the wall studs, the bottom plate of the wall, and the perimeter of the ceiling. The set crews then join each side-by-side module at its marriage wall with carriage bolts in the basement. The resulting basement carrying beam, which is made up of four to six members, is very strong.

Portable classrooms are built at low cost and excellent quality in a factory-controlled environment and its difficult for the naked eye to tell the difference between traditional construction and a portable classroom anymore. Considering the inflexibility of school schedules its nice to know that there won't be any construction delays caused by weather. The portable classroom will be built and on-site over the summer with no worries.

Many school districts are actually mandating that a certain percentage of new construction be portable classrooms which makes sense if you think about it. It's difficult to predict the school enrollments more than five or ten years into the future and portable classrooms provide the flexibility to meet spikes in demand by simply moving a portable classroom from one location to another. And as for durability, you can expect a portable classroom to last just as long if not longer than a traditional stick-built classroom.