Timbers were set into the upper courses of most walls to stiffen them. Massive exterior buttresses were also employed to fortify wall sections (see the photo at right), but this method of reinforcement required the inclusion of pilasters on the inside of the building to resist the thrust of the buttresses and prevent the collapse of the wall. Pilasters and buttresses were often composed of more durable baked brick, even when the walls they supported were adobe. When the walls got too high for workers on the ground to reach the top, simple wood scaffolding was erected from whatever lumber was available. Many times posts were temporarily cemented into the walls to support catwalks. When the wall was completed, the posts were removed and the voids filled with adobe, or were sometimes sawed off flush with the surface of the wall.