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.
It is customary, whenever the walls of a building are covered with clapboards, to make a special finish at the corners. This finish usually takes the form of two boards, one about 5 inches wide, the other 3 7/8 inches wide by about 1 1/8 inches thick, placed vertically at each side of the corner so as to project 1 1/8 inches- the thickness of the board - beyond the face of the sheathing. Thus they form something for the clapboards to be fitted against. The corner boards may be mitered at the corner, but this is not desirable, as it is hard to make such a joint so that it will not open up under the influence of the weather. The corner boards are, therefore, usually finished at the corner with a simple butt joint, the two pieces being securely nailed together. In some styles of work it may be well to give the corner boards a special character, and this can be done by crowning them at the top with a capital, so that they will form a sort of pilaster at each corner of the house. A base may also be added if desired, though it is hard to make a base finish well on top of the water table. Fig. 275 shows a view of a simple corner board in place on the outside corner of a house. A is the corner board, B is the clapboarding, C is the water table, and D is the foundation wall. Fig. 276 shows a section taken horizontally through the corner of a building with corner boards and clapboards, showing how the corner boards are applied to the outside boarding. In this figure, A is one of the corner boards, B is the outside sheathing, C is the studding at the corner built up of 2 X 4-inch pieces, and D are the clapboards. The width of the boards may, of course, be varied to suit the taste of the designer.
Fig. 275. Simple Corner Board in Place.
Fig. 276. Section Showing Corner Board Construction.
When the walls of the building are to be covered with shingles it is not necessary to have corner boards, as the shingles can be brought together at the corner and made to finish nicely against each other. The usual method is to allow the shingles on the adjacent sides to lap over each other alternately as shown at A in Fig. 277.