Wood siding how-to -- Part B -- Corner Details
Siding Details: A, Miter corner; B, metal corners; C, corner boards.
The method of finishing wood siding or other materials at exterior corners is often influenced by the overall design of the house.
A mitered corner effect on horizontal siding or the use of corner boards are perhaps the most common methods of treatment.
Mitering corners (Figure A) of bevel and similar sidings, unless carefully done to prevent openings, is not always satisfactory. To maintain a good joint, it is necessary that the joint fit tightly the full depth of the miter. It also is good practice to treat the ends with water-repellent preservative prior to nailing.
Metal corners (Figure B) are perhaps more commonly used than the mitered corner and give a mitered effect. They are easily placed over each corner as the siding is installed. The metal corners should fit tightly without openings and be nailed on each side to the sheathing or corner stud beneath. If made of galvanized iron, they should be cleaned with a mild acid wash and primed with a metal primer before the house is painted to prevent early peeling of the paint. Weathering of the metal also will prepare it for the prime paint coat.
Siding Details: D, siding return at roof.
Corner boards of various types and sizes may be used for horizontal sidings of all types (Figure C). They also provide a satisfactory termination for plywood and similar sheet materials. Corner boards are often made of 1 1/8- or 1 3/8-inch thick material. Plain outside casing commonly used for window and door frames can be adapted for corner boards.
When siding returns against a roof surface -- such as at a dormer -- there should be a clearance of about 2 inches (Figure D). Siding cut tight against the shingles retains moisture after rains and usually results in peeling paint. Shingle flashing extending well up on the dormer wall will provide the necessary resistance to entry of wind-driven rain. Here again, a water-repellant preservative should be used on the ends of the siding at the roofline.
Siding Details: E, interior corner.
Interior corners (Figure E) are butted against a square corner board of nominal 1 1/4- or 1 3/8-inch size, depending on the thickness of the siding.
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