Since a silo cannot be economically built inside of a rectangular barn, the first comparison is made with the barns simply enclosed, altho one of the chief advantages of a round barn is the deep silo which it is possible to build so economically in the center.

Fig. 9. Showing construction of mortise frame barn, side view.

Another item of economy in the circular barn is less framing lumber. This form has the strongest possible construction with the least lumber in the frame, and the least bracing, not a single timber larger than a 2 × 6 being required above the sill. The arched circular roof requires no supports, and no scaffolding is needed inside during its construction.

The accompanying tables show the comparative amount and value of lumber and cubical content in round barns 60 and 90 feet in diameter, and rectangular barns of equal area and height of posts.

Table 1A.—A Comparison of the Cost of Material in Round and Rectangular Barns of the Same Area, Not Including Foundation and Silos

Rectangular barn, 36 × 781⁄2 ft.
Round Barn
60 feet in diameter		Plank frameMortise frame
Framing lumber13,976 ft. @ $25 = $349.4019,833 ft. @ $25 = $495.8329,074 ft. @ $25 = $726.85
Sheathing, siding, and flooring12,971 ft. @ $22 = 285.3615,355 ft. @ $22 = 337.8115,355 ft. @ $22 = 337.81
Shingles44,000 @ $3.75 = 165.0045,000 @ $3.75 = 168.7545,000 @ $3.75 = 168.75
Bolts 20.88
Total cost of lumber $799.76$1023.27$1233.41
Content, cubic feet 117,669117,138117,138

Table 1B.

Rectangular barn, 36 × 1763⁄4 ft.
Round barn,
90 feet in diameter		Plank frameMortise frame
Framing lumber30,899 ft. @ $25 = $772.4838,815 ft. @ $25 = $970.3859,481 ft. @ $25 = $1487.03
Sheathing, siding, and flooring22,375 ft. @ $22 = 492.2528,547 ft. @ $22 = 628.0328,547 ft. @ $22 = 628.03
Shingles97,000 @ $3.75 = 363.75 102,000 @ $3.75 = 382.50102,000 @ $3.75 = 382.50
Bolts 26.76
Total cost of lumber$1628.48$2007.67$2497.56
Content, cubic feet322,952270,570270,570