Another modification should be adopted: the joists, so far as possible, should rest on sills and beams and not be gained into them. It is unwise and unscientific to cut gains for the reception of the ends of the joists at considerable expense, since such gains weaken both joists and sills. In most cases the joists may be placed on top of the sills, thereby obviating the necessity of framing, while preserving the strength of sill and joist entire. When it is desirable, as it often is in small structures, to have the top of the sill or beam coincide with the tops of the joists, it is cheaper and better to use a rather light timber and fortify it by nailing upon it 2 × 4-inch studding ([Fig. 109]), thereby avoiding the necessity of cutting gains, while giving additional strength to the timber which supports the joists.
Fig. 109. Laying the joist.
The joists in barns should be bridged as in houses. That part of the barn floor which is above the root-cellar should be deafened, as shown in [Fig. 101]. Cleats nailed on the sides of the joists serve to support the short boards which carry the deafening material. The 2-inch space between the false and the true floor is filled with mortar composed of about five or six parts of sand to one of lime or cement. If all of the floor driven upon above the basement is deafened, it will deaden sound and promote warmth in the lower story.
While the balloon frame has been almost universally adopted in the construction of houses, it is only recently that large barn frames have been successfully constructed on the same general principles. The plank frame has now been so modified and improved that it serves well for the largest farm building. All of the frame timbers are sawed two inches thick and of variable widths, as required. Instead of uniting the timbers by means of mortise and tenon, they are fastened with wire spikes. This new method secures as strong a frame as the old, and saves from 30 to 40 per cent of material, while the plank frame is more easily and cheaply erected than the large timbered frame is. The 2-inch frame material can be so placed as to direction and position that it will secure the maximum of strength with the minimum of lumber.
Fig. 110. Barn frame.
Fig. 111. Cross-section of the frame.
