Abstract: A relocatable modular building, formed of a plurality of external wall portions. Each wall portion includes a plurality of small, integral molded plastic panels disposed adjacent to one another. The panels include interlocking means to facilitate the erection of the wall and to strengthen the erected wall. A plurality of bolts join immediately adjacent panels to one another to form the wall portions. Each wall portion includes weatherproof gasketing material interposed between the immediately adjacent panels. Windows and a door are provided in respective wall portions of the building.