Let’s take an example. Suppose you want to figurethe board measure of a piece of lumber 10 feet long by10 inches wide by 1 inch thick. Scan down the column(fig. 2-12, view B) headed by the 12-inch graduation to10, and then go horizontally to the left to the figuredirectly below the 10-inch graduation. You will find thefigure to be 84, or 8 4/12 board feet. For easiercalculating purposes, you can convert 8 4/12 to adecimal (8.33).To calculate the cost of this piece of lumber,multiply the cost per board foot by the total number ofboard feet. For example, a 1 by 10 costs
||content||
.15 per boardfoot. Multiply the cost per board foot (
||content||
. 15) by thenumber of board feet (8.33). This calculation is asfollows:What do you do if the piece is more than 1 inchthick? All you have to do is multiply the result obtainedfor a 1-inch-thick piece by the actual thickness of thepiece in inches. For example, if the board described inthe preceding paragraph were 5 inches thick instead of1 inch thick, you would follow the procedure describedand then multiply the result by 5.The board measure scale can be read only forlumber from 8 to 15 feet in length. If your piece is longerthan 15 feet, you can proceed in one of two ways. If thelength of the piece is evenly divisible by one of thelengths in the table, you can read for that length andmultiply the result by the number required to equal thepiece you are figuring. Suppose you want to find thenumber of board feet in a piece 33 feet long by 7 incheswide by 1 inch thick. Since 33 is evenly divisible by 11,scan down the 12-inch column to 11 and then go left tothe 7-inch column. The figure given there (which is65/12, or 6.42 bd. ft.) is one-third of the total board feet.The total number of board feet is 6 5/12 (or 6.42) x 3,or 19 3/12 (or 19.26) board feet.If the length of the piece is not evenly divisible byone of the tabulated lengths, you can divide it into twotabulated lengths, read the table for these two, and addthe results together. For example, suppose you want tofind the board measure of a piece 25 feet long by10 inches wide by 1 inch thick. This length can bedivided into 10 feet and 15 feet. The table shows that the10-foot length contains 8 4/12 (8.33) board feet and the15-foot length contains 12 6/12 (12.5) board feet. Thetotal length then contains 8 4/12 (8.33) plus 12 6/12(12.5), or 20 10/12 (20.83) board feet.Figure 2-13.—Framework of a gable roof.Figure 2-14.—Typical common rafter with an overhang.DESIGNSLEARNING OBJECTIVE: Upon completingthis section, you should be able to describeprocedures for the layout and installation ofmembers of gable, hip, intersecting, and shedroof designs.As we noted earlier, the four most common roofdesigns you will encounter as a Builder are gable, hip,intersecting, and shed. In this section, we will examine2-10