To study historic timber barns, the simple systems used to enclose them are a tremendous aid in seeing all of the various parts. Since barns are typically unheated storage buildings, the enclosure of the walls is accomplished by simply nailing boards to the exterior surface of the frame. In Ohio these boards are much more often vertical than horizontal. In some cases narrow strips of wood called "battens" are nailed over the vertical seams to further weatherproof the barn. The roof is covered in a similar fashion by either applying continuous horizontal boards referred to as "sheathing" or narrow horizontal boards spaced several inches apart, referred to as "skip sheathing."
In early 19th century barns the roof sheathing was covered with wooden shakes. These "shake shingles" were split from white or red oak billets using wedges and clubs to form sections that were then carefully "riven" with a froe to a consistent size and thickness. By the early 20th Century, more durable roofing was provided using "standing seam" galvanized steel or thin slates. The steel roofing was supplied by the mills that had grown up in the big industrial cities of the Great Lakes, while the roof slates were transported by rail from the Vermont-New York, and Eastern Pennsylvania quarries. These "stone shingles" were hand split from larger quarried blocks. The use of slate in America can be traced to the colonial period, but in Ohio its popularity was dependent on improved transportation, first by canal and quickly thereafter, by rail freight. By the 1880s slate had established itself as a competitive roofing material (Stephens 1995, 246).
A heavy and durable roof material, slate’s thickness is the critical factor in determining weight. "A modest-sized barn having thirty squares of standard three-eights-inch slate shingles would require, at a minimum, nine tons of roofing material (Stephens 1995, 247). Where farmers could afford the additional expense, decorated patterns produced by different colored slates, or dates, names, or initials were incorporated in the roof. The pattern of decorated slate roofs shows that most of them were erected in the northern half of the state, reflecting the greater agricultural productivity and prosperity in that area. Many beautiful slate roofs on Ohio barns are now over a century old and bear the date to prove it.