Joints over framing
All joints where two pieces meet end to end must occur over framing. Butt joints are recommended for both horizontal and vertical trim. In runs of 16′ or less, the ends should lightly touch. Runs over 16 feet require a gap of 1/8 inch, which should be sealed with exterior caulk. Attach to the framing members with two nails on each side of the joint. Drill pilot holes first to avoid splitting.
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