Heavy Timber Barns

HEAVY TIMBER BARNS General Framing Plan. Fig. 120 shows the general plan of a barn frame of a building 38 by 64 feet, with 16-foot main posts, gambrel roof, basement, and double driveway floors. It is typical heavy timber construction, with boxed mortise-and-tenon joints.

One point worthy of note for storage barns such as this, is the effort to get height—not width—to get as much under a given amount of roof as possible. That this is an advantage, has been slowly but well learned; the farmer will tell you that the bay or mow is only half full when filled even with the main plates. The weight of the portion to be stored above keeps pressing the lower part down—an advantage that is lost in the low, wide barn. All the crops are lifted by means of rope and tackle, and carried by means of a steel track and car the full length of the barn just under the ridge of the roof, and then dropped to their proper places in the bays, mows, or the loft, over the drive way floors, the power being furnished by a horse team.

Another important principle in the construc tion of these buildings is that no timbers sup porting a heavy load—as beams, cross-sills, etc.—are' made to rest on their tenons alone, but all have a shoulder or bearing across the whole end of the stick.

The drawing shows the ends of beams boxed into the posts, while the ends of the cross-sills have a bearing on the end of the basement posts below. Good framing requires also that no braces shall hold against the tenon alone, but they should have a boxing of at least one-half inch in depth.

Another important principle is that of draw bore pinning. By this is meant pins that hold the tenons; ordinary drift bolts or spikes would not do, as a pin made of wood is larger than the iron ones would be, and will not side-cut or press into the wood so much as the iron ones would do under a heavy load. Also, the pins must have a long taper, to give draw. The draw-bore holes in the tenon and those through the mortise are given one-eighth inch draw or variation in such direction as will tend to pull the tenon and seizing tighter into the mortise and boxing. That is to say, the distance from

the joint to the draw-bore hole is one-eighth inch greater in the mortise than in the tenon.

All of the large cross-timbers should be of whole sticks—not spliced—that is, the beams and cross-sills in particular; but the main sills and plates may be spliced at every bent or post if desired. Sometimes long timbers are very hard to get, in which case the width of the barn can be made to conform to length of timbers obtainable, from 30 to 40 feet.

Some people have a notion that several planks spiked together will make a stronger stick of timber than a solid one. This is not true; after having tried it many times, the writer is prepared to say that you can make a stick fairly stiff one way; but, with all the spikes you can drive, it cannot be made as stiff the other way.

The length and number of posts in such a barn are entirely arbitrary, depending on the Fig. 121. Truss for Barn without Basement Posts.

size of barn desired. The height of the purlin plates is also variable.

This kind of barn is built to best advantage on a gentle hillside, thus allowing an easy drive way to the main floor of the barn, and giving opportunity for a basement underneath to afford valuable storage room for implements; this basement space also provides warm stables. While there are other forms of heavy timber construction which afford greater strength than Fig. 122. Details of Heavy Framing.

that shown in the drawing, this method has been found to answer every purpose; and the added advantages of other methods of framing seldom warrant the difference in cost.

At first glance at the construction shown in Fig. 120, one would think such a frame a wilder ness of timbers. As a matter of fact, however, the system is simple, and the number of names of different members or parts is not great. The accompanying list gives the names and sizes of the different numbered parts :