After the log cuts are set on end, the froe is held on the upper end of the block and then struck a blow with a wooden maul which causes a piece of the block or shake to split off. Being hand-split, the thickness varies somewhat; the minimum is ½ inch. A roof of thin shingles, lacking sufficient scale, is never as effective as a rough textured one, using ¾- to 1¼-inch thick shakes, to harmonize with the sturdy appearance of the log walls. The width, normally 6 to 8 inches, is governed by the size of the blocks of wood and varies accordingly, while the length is governed by the spacing of the roof logs or purlins. Shakes are always laid on the purlins in single courses, lapping the sides 1½ to 2 inches and over-lapping the ends at least 6 inches, as illustrated in [figure 19]. Nailing is usually done with six- or eight-penny galvanized box nails. Copper nails may be used for greater permanence. A good shake roof will not leak although from the inside of the building it may appear to have many holes.
The ordinary, uninteresting, straight-line effect at the butts may be broken up by staggering them from 1 to 2 inches, as is often done with shingles. This method produces an effect more in keeping with the log walls. Although involving greater care and additional labor it is preferable, from an architectural point of view, to the more common custom of laying them to uniformly straight lines.
At the ridge of the roof, where the shingles or shakes intersect, provisions must be made for weatherproofing. The shingled Boston ridge, comb intersection, or pole ridge, shown in [figure 21] are practical and much more satisfactory from the standpoint of architectural effect than stock metal ridges, ridge boards, and other methods.
Figure 21.—Ridge treatments.
If the log building is to be divided into several rooms, at least two different methods may be used to construct the partition walls. If the log construction plan is to be carried throughout the structure by using interior log-wall partitions, these should be laid out and framed in, and the door openings cut in the same manner as previously described for exterior walls. If a log partition comes at a place in a cross wall where it is not considered desirable to have the log ends project into the room beyond the opposite face of the wall, they may be sawed off flush with the face of the cross wall, as shown at X, [figure 22], Plan A. This will not weaken the joint since the logs are both pinned and locked in place.
