Not counting things like geodesic domes and igloos, all houses have at least four outside corners. These are important design elements, and the treatment they receive can have a big effect on a structure's appearance. Let's take a look at three common corner details used with wood siding: corner boards, woven corners, and mitered corners.
Corner boards
The simplest and most popular approach to finishing outside corners is installing corner boards. There's good reason for this: Corner boards provide a visual break from the horizontal lines of siding, in much the same way that corner pilasters and columns do. The effect can be reinforced by painting or staining the corner boards a different color than the siding. 
To achieve a pleasing sense of scale, corner boards should be sized with both the width of the siding and the overall height of the structure in mind. As with actual columns, increased height calls for added heft. The 4-inch corner boards that look just right on a single-story house sided with narrow clapboards may seem much too light and wimpy on an otherwise similar two-story house.
As strong visual elements, corner boards should also stand proud of the siding. This is most often done by using 5/4 trim stock. For an even stronger effect, the corner boards can be padded out to create a slot that encloses the ends of the siding or the edges of the shingles (see figure below). This detail also provides some margin for error in fitting the siding, beca
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