A structural assembly such as for use in constructing a living space of a recreational vehicle includes a wall with vertical rails at the top and bottom. The rails fitting into complementary recess within floor and ceiling members. The bottom rail has a curved cross section and fits into a complementary shaped curved channel in a floor member such that to assemble the wall to the floor, the wall is rested on the floor member at an angle and is then tilted upright to lock it to the floor member. A first keeper is then placed into a gap between the wall and the floor member, and acts in compression to prevent rotation of the wall. A second keeper has portions that fit into recesses in the wall and the ceiling members, respectively. The second keeper acts in tension to prevent vertical separation of the wall and the ceiling.