This section is from the book "Cyclopedia Of Architecture, Carpentry, And Building", by James C. et al. Also available from Amazon: Cyclopedia Of Architecture, Carpentry And Building.
The clapboards used for covering walls are usually of white pine or spruce, though they are sometimes made from a cheaper timber such as hemlock or fir. They are about 5 or 6 inches wide and about 4 feet long and are thicker on one side or edge than on the other. The thicker edge measures about 1/2 inch while the thin edge is only about 1/8 inch thick. Each clapboard, therefore, is as shown in Fig. 272, where A is an elevation and B is a section of the board. The tapering section is obtained by sawing the boards from a log, cutting each time from the circumference inward. The boards are thus all quarter sawed and shrink evenly, if at all, when they are exposed. When laid up on the side of a building, the clapboards should lap over each other at least 1 1/2 inches, as shown in Fig. 273.
This term "to the weather" is made use of in many specifications to indicate the amount of board which is to be exposed. Thus, "4 inches to the weather" means that 4 inches will be exposed. Building paper should be placed between the clapboarding and the sheathing, as shown at D, to keep out the weather.
Fig. 272. Side and End Views of a Clapboard.
Fig. 273. Section Showing Method of Laying Clapboards.